doc: fix documentation for hwtimer
doc: fix documentation for hwtimer

@verbatim was used incorrectly and a closing html tag was missing

plushvoxel/RIOT,PSHIVANI/Riot-Code,alex1818/RIOT,ks156/RIOT,koenning/RIOT,thiagohd/RIOT,thomaseichinger/RIOT,tdautc19841202/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,mfrey/RIOT,kaspar030/RIOT,toonst/RIOT,Yonezawa-T2/RIOT,changbiao/RIOT,rakendrathapa/RIOT,rfuentess/RIOT,backenklee/RIOT,biboc/RIOT,automote/RIOT,bartfaizoltan/RIOT,marcosalm/RIOT,hamilton-mote/RIOT-OS,Lexandro92/RIOT-CoAP,dhruvvyas90/RIOT,changbiao/RIOT,jremmert-phytec-iot/RIOT,daniel-k/RIOT,FrancescoErmini/RIOT,Darredevil/RIOT,Hyungsin/RIOT-OS,neiljay/RIOT,1blankz7/RIOT,DipSwitch/RIOT,authmillenon/RIOT,BytesGalore/RIOT,DipSwitch/RIOT,jbeyerstedt/RIOT-OTA-update,arvindpdmn/RIOT,nsol-nmsu/RIOT,LudwigKnuepfer/RIOT,alignan/RIOT,asanka-code/RIOT,JensErdmann/RIOT,jasonatran/RIOT,neumodisch/RIOT,ntrtrung/RIOT,1blankz7/RIOT,ntrtrung/RIOT,PSHIVANI/Riot-Code,RubikonAlpha/RIOT,jhollister/RIOT,rakendrathapa/RIOT,shady33/RIOT,benoit-canet/RIOT,kb2ma/RIOT,kushalsingh007/RIOT,ant9000/RIOT,emmanuelsearch/RIOT,sumanpanchal/RIOT,altairpearl/RIOT,roberthartung/RIOT,gbarnett/RIOT,haoyangyu/RIOT,rousselk/RIOT,josephnoir/RIOT,1blankz7/RIOT,katezilla/RIOT,daniel-k/RIOT,adrianghc/RIOT,attdona/RIOT,aeneby/RIOT,centurysys/RIOT,plushvoxel/RIOT,stevenj/RIOT,neiljay/RIOT,mziegert/RIOT,BytesGalore/RIOT,jferreir/RIOT,herrfz/RIOT,A-Paul/RIOT,dailab/RIOT,jremmert-phytec-iot/RIOT,jferreir/RIOT,gebart/RIOT,sgso/RIOT,tfar/RIOT,abkam07/RIOT,ThanhVic/RIOT,avmelnikoff/RIOT,chris-wood/RIOT,Osblouf/RIOT,Darredevil/RIOT,jhollister/RIOT,Osblouf/RIOT,l3nko/RIOT,hamilton-mote/RIOT-OS,gautric/RIOT,patkan/RIOT,kerneltask/RIOT,robixnai/RIOT,LudwigKnuepfer/RIOT,ximus/RIOT,rakendrathapa/RIOT,aeneby/RIOT,beurdouche/RIOT,cladmi/RIOT,kaleb-himes/RIOT,ks156/RIOT,jferreir/RIOT,rousselk/RIOT,openkosmosorg/RIOT,openkosmosorg/RIOT,Josar/RIOT,syin2/RIOT,kaleb-himes/RIOT,DipSwitch/RIOT,luciotorre/RIOT,l3nko/RIOT,smlng/RIOT,RIOT-OS/RIOT,herrfz/RIOT-old,aeneby/RIOT,emmanuelsearch/RIOT,EmuxEvans/RIOT,mtausig/RIOT,rakendrathapa/RIOT,rajma996/RIOT,watr-li/RIOT,authmillenon/RIOT,DipSwitch/RIOT,RubikonAlpha/RIOT,jasonatran/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,ThanhVic/RIOT,toonst/RIOT,stevenj/RIOT,changbiao/RIOT,kbumsik/RIOT,thiagohd/RIOT,khhhh/RIOT,tdautc19841202/RIOT,chris-wood/RIOT,neumodisch/RIOT,binarylemon/RIOT,tdautc19841202/RIOT,OlegHahm/RIOT,rajma996/RIOT,roberthartung/RIOT,Osblouf/RIOT,dkm/RIOT,immesys/RiSyn,LudwigOrtmann/RIOT,basilfx/RIOT,yogo1212/RIOT,roberthartung/RIOT,syin2/RIOT,Darredevil/RIOT,rousselk/RIOT,patkan/RIOT,rajma996/RIOT,A-Paul/RIOT,roberthartung/RIOT,abp719/RIOT,altairpearl/RIOT,gebart/RIOT,jferreir/RIOT,hamilton-mote/RIOT-OS,phiros/RIOT,fnack/RIOT,automote/RIOT,alignan/RIOT,Osblouf/RIOT,benoit-canet/RIOT,malosek/RIOT,MonsterCode8000/RIOT,fnack/RIOT,kaleb-himes/RIOT,sumanpanchal/RIOT,ant9000/RIOT,mtausig/RIOT,OTAkeys/RIOT,kushalsingh007/RIOT,d00616/RIOT,jfischer-phytec-iot/RIOT,mfrey/RIOT,latsku/RIOT,adrianghc/RIOT,chris-wood/RIOT,katezilla/RIOT,sumanpanchal/RIOT,ximus/RIOT,khhhh/RIOT,OTAkeys/RIOT,dailab/RIOT,d00616/RIOT,herrfz/RIOT-old,haoyangyu/RIOT,neumodisch/RIOT,RubikonAlpha/RIOT,ant9000/RIOT,OlegHahm/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,dailab/RIOT,wentaoshang/RIOT,x3ro/RIOT,Darredevil/RIOT,emmanuelsearch/RIOT,rajma996/RIOT,watr-li/RIOT,kb2ma/RIOT,stevenj/RIOT,rfswarm/RIOT,adjih/RIOT,centurysys/RIOT,alignan/RIOT,luciotorre/RIOT,kushalsingh007/RIOT,biboc/RIOT,herrfz/RIOT,A-Paul/RIOT,yogo1212/RIOT,FrancescoErmini/RIOT,dhruvvyas90/RIOT,altairpearl/RIOT,biboc/RIOT,msolters/RIOT,binarylemon/RIOT,avmelnikoff/RIOT,JensErdmann/RIOT,alignan/RIOT,kerneltask/RIOT,1blankz7/RIOT,attdona/RIOT,immesys/RiSyn,abkam07/RIOT,Osblouf/RIOT,jasonatran/RIOT,MohmadAyman/RIOT,phiros/RIOT,jremmert-phytec-iot/RIOT,authmillenon/RIOT,msolters/RIOT,jfischer-phytec-iot/RIOT,avmelnikoff/RIOT,abkam07/RIOT,d00616/RIOT,plushvoxel/RIOT,MarkXYang/RIOT,malosek/RIOT,latsku/RIOT,altairpearl/RIOT,gbarnett/RIOT,ximus/RIOT,dkm/RIOT,RIOT-OS/RIOT,alignan/RIOT,kb2ma/RIOT,Yonezawa-T2/RIOT,stevenj/RIOT,phiros/RIOT,abp719/RIOT,PSHIVANI/Riot-Code,alex1818/RIOT,dailab/RIOT,Josar/RIOT,changbiao/RIOT,attdona/RIOT,sumanpanchal/RIOT,kaspar030/RIOT,DipSwitch/RIOT,luciotorre/RIOT,thiagohd/RIOT,binarylemon/RIOT,FrancescoErmini/RIOT,MarkXYang/RIOT,jfischer-phytec-iot/RIOT,TobiasFredersdorf/RIOT,ntrtrung/RIOT,rfuentess/RIOT,miri64/RIOT,LudwigOrtmann/RIOT,roberthartung/RIOT,asanka-code/RIOT,shady33/RIOT,altairpearl/RIOT,abp719/RIOT,marcosalm/RIOT,lazytech-org/RIOT,patkan/RIOT,Josar/RIOT,basilfx/RIOT,jremmert-phytec-iot/RIOT,EmuxEvans/RIOT,thiagohd/RIOT,herrfz/RIOT,AnonMall/RIOT,plushvoxel/RIOT,haoyangyu/RIOT,rfswarm2/RIOT,AnonMall/RIOT,ks156/RIOT,lazytech-org/RIOT,OTAkeys/RIOT,zhuoshuguo/RIOT,smlng/RIOT,cladmi/RIOT,smlng/RIOT,sgso/RIOT,gautric/RIOT,gbarnett/RIOT,FrancescoErmini/RIOT,EmuxEvans/RIOT,zhuoshuguo/RIOT,zhuoshuguo/RIOT,kushalsingh007/RIOT,ThanhVic/RIOT,changbiao/RIOT,LudwigOrtmann/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,biboc/RIOT,tdautc19841202/RIOT,beurdouche/RIOT,latsku/RIOT,basilfx/RIOT,dkm/RIOT,AnonMall/RIOT,jasonatran/RIOT,OTAkeys/RIOT,arvindpdmn/RIOT,alex1818/RIOT,gautric/RIOT,Darredevil/RIOT,josephnoir/RIOT,mziegert/RIOT,immesys/RiSyn,daniel-k/RIOT,binarylemon/RIOT,mtausig/RIOT,stevenj/RIOT,avmelnikoff/RIOT,rfswarm/RIOT,mziegert/RIOT,kbumsik/RIOT,kaspar030/RIOT,rfswarm2/RIOT,mtausig/RIOT,A-Paul/RIOT,AnonMall/RIOT,LudwigOrtmann/RIOT,yogo1212/RIOT,Yonezawa-T2/RIOT,kYc0o/RIOT,miri64/RIOT,ThanhVic/RIOT,RubikonAlpha/RIOT,authmillenon/RIOT,FrancescoErmini/RIOT,MohmadAyman/RIOT,automote/RIOT,fnack/RIOT,x3ro/RIOT,backenklee/RIOT,RBartz/RIOT,jhollister/RIOT,herrfz/RIOT-old,mtausig/RIOT,l3nko/RIOT,basilfx/RIOT,OlegHahm/RIOT,rfswarm/RIOT,RIOT-OS/RIOT,ks156/RIOT,MohmadAyman/RIOT,JensErdmann/RIOT,jferreir/RIOT,rousselk/RIOT,zhuoshuguo/RIOT,lebrush/RIOT,authmillenon/RIOT,TobiasFredersdorf/RIOT,x3ro/RIOT,ThanhVic/RIOT,LudwigKnuepfer/RIOT,BytesGalore/RIOT,shady33/RIOT,wentaoshang/RIOT,RBartz/RIOT,abp719/RIOT,centurysys/RIOT,cladmi/RIOT,brettswann/RIOT,gbarnett/RIOT,Ell-i/RIOT,Lexandro92/RIOT-CoAP,RBartz/RIOT,arvindpdmn/RIOT,immesys/RiSyn,kb2ma/RIOT,nsol-nmsu/RIOT,sumanpanchal/RIOT,haoyangyu/RIOT,tfar/RIOT,stevenj/RIOT,neiljay/RIOT,luciotorre/RIOT,herrfz/RIOT-old,MohmadAyman/RIOT,benoit-canet/RIOT,RubikonAlpha/RIOT,kerneltask/RIOT,patkan/RIOT,robixnai/RIOT,biboc/RIOT,l3nko/RIOT,aeneby/RIOT,koenning/RIOT,centurysys/RIOT,jremmert-phytec-iot/RIOT,lebrush/RIOT,TobiasFredersdorf/RIOT,ximus/RIOT,rfswarm2/RIOT,kYc0o/RIOT,jhollister/RIOT,brettswann/RIOT,AnonMall/RIOT,d00616/RIOT,alex1818/RIOT,1blankz7/RIOT,hamilton-mote/RIOT-OS,Ell-i/RIOT,sgso/RIOT,Lexandro92/RIOT-CoAP,mfrey/RIOT,beurdouche/RIOT,lazytech-org/RIOT,tdautc19841202/RIOT,RBartz/RIOT,latsku/RIOT,jferreir/RIOT,sumanpanchal/RIOT,TobiasFredersdorf/RIOT,shady33/RIOT,centurysys/RIOT,BytesGalore/RIOT,binarylemon/RIOT,benoit-canet/RIOT,daniel-k/RIOT,rakendrathapa/RIOT,OlegHahm/RIOT,rfswarm/RIOT,miri64/RIOT,thomaseichinger/RIOT,tdautc19841202/RIOT,latsku/RIOT,marcosalm/RIOT,OTAkeys/RIOT,adjih/RIOT,rajma996/RIOT,adrianghc/RIOT,backenklee/RIOT,bartfaizoltan/RIOT,abp719/RIOT,centurysys/RIOT,MonsterCode8000/RIOT,latsku/RIOT,Osblouf/RIOT,jhollister/RIOT,rfswarm/RIOT,Lexandro92/RIOT-CoAP,attdona/RIOT,malosek/RIOT,khhhh/RIOT,tfar/RIOT,BytesGalore/RIOT,PSHIVANI/Riot-Code,MonsterCode8000/RIOT,LudwigKnuepfer/RIOT,kYc0o/RIOT,altairpearl/RIOT,katezilla/RIOT,robixnai/RIOT,herrfz/RIOT,kbumsik/RIOT,patkan/RIOT,cladmi/RIOT,phiros/RIOT,jbeyerstedt/RIOT-OTA-update,bartfaizoltan/RIOT,rfuentess/RIOT,robixnai/RIOT,Ell-i/RIOT,neumodisch/RIOT,toonst/RIOT,daniel-k/RIOT,mziegert/RIOT,dkm/RIOT,haoyangyu/RIOT,LudwigKnuepfer/RIOT,neiljay/RIOT,ximus/RIOT,malosek/RIOT,josephnoir/RIOT,AnonMall/RIOT,Lexandro92/RIOT-CoAP,nsol-nmsu/RIOT,shady33/RIOT,brettswann/RIOT,neumodisch/RIOT,gautric/RIOT,brettswann/RIOT,neumodisch/RIOT,TobiasFredersdorf/RIOT,luciotorre/RIOT,wentaoshang/RIOT,EmuxEvans/RIOT,josephnoir/RIOT,Hyungsin/RIOT-OS,attdona/RIOT,gebart/RIOT,rajma996/RIOT,chris-wood/RIOT,watr-li/RIOT,neiljay/RIOT,jhollister/RIOT,thiagohd/RIOT,dhruvvyas90/RIOT,adjih/RIOT,adrianghc/RIOT,sgso/RIOT,miri64/RIOT,tfar/RIOT,lebrush/RIOT,lebrush/RIOT,beurdouche/RIOT,LudwigOrtmann/RIOT,syin2/RIOT,ks156/RIOT,phiros/RIOT,lebrush/RIOT,x3ro/RIOT,openkosmosorg/RIOT,automote/RIOT,ntrtrung/RIOT,arvindpdmn/RIOT,gebart/RIOT,lebrush/RIOT,herrfz/RIOT-old,bartfaizoltan/RIOT,hamilton-mote/RIOT-OS,kaspar030/RIOT,herrfz/RIOT,mziegert/RIOT,LudwigOrtmann/RIOT,l3nko/RIOT,authmillenon/RIOT,mziegert/RIOT,wentaoshang/RIOT,kushalsingh007/RIOT,marcosalm/RIOT,lazytech-org/RIOT,smlng/RIOT,arvindpdmn/RIOT,abkam07/RIOT,msolters/RIOT,gebart/RIOT,koenning/RIOT,mfrey/RIOT,luciotorre/RIOT,gautric/RIOT,zhuoshuguo/RIOT,rfswarm2/RIOT,d00616/RIOT,khhhh/RIOT,1blankz7/RIOT,backenklee/RIOT,x3ro/RIOT,watr-li/RIOT,yogo1212/RIOT,DipSwitch/RIOT,abkam07/RIOT,arvindpdmn/RIOT,bartfaizoltan/RIOT,ant9000/RIOT,robixnai/RIOT,ntrtrung/RIOT,ntrtrung/RIOT,kYc0o/RIOT,yogo1212/RIOT,marcosalm/RIOT,robixnai/RIOT,marcosalm/RIOT,cladmi/RIOT,asanka-code/RIOT,openkosmosorg/RIOT,herrfz/RIOT,Hyungsin/RIOT-OS,fnack/RIOT,thomaseichinger/RIOT,A-Paul/RIOT,haoyangyu/RIOT,rfswarm2/RIOT,patkan/RIOT,MarkXYang/RIOT,Yonezawa-T2/RIOT,RIOT-OS/RIOT,kushalsingh007/RIOT,JensErdmann/RIOT,l3nko/RIOT,rfswarm2/RIOT,RubikonAlpha/RIOT,rfswarm/RIOT,aeneby/RIOT,MarkXYang/RIOT,Lexandro92/RIOT-CoAP,foss-for-synopsys-dwc-arc-processors/RIOT,benoit-canet/RIOT,FrancescoErmini/RIOT,brettswann/RIOT,emmanuelsearch/RIOT,koenning/RIOT,avmelnikoff/RIOT,jbeyerstedt/RIOT-OTA-update,dhruvvyas90/RIOT,EmuxEvans/RIOT,alex1818/RIOT,gbarnett/RIOT,rousselk/RIOT,sgso/RIOT,openkosmosorg/RIOT,dhruvvyas90/RIOT,chris-wood/RIOT,koenning/RIOT,changbiao/RIOT,MohmadAyman/RIOT,sgso/RIOT,Darredevil/RIOT,kYc0o/RIOT,immesys/RiSyn,thomaseichinger/RIOT,fnack/RIOT,abkam07/RIOT,PSHIVANI/Riot-Code,adjih/RIOT,kerneltask/RIOT,PSHIVANI/Riot-Code,Ell-i/RIOT,Yonezawa-T2/RIOT,syin2/RIOT,Hyungsin/RIOT-OS,abp719/RIOT,JensErdmann/RIOT,jremmert-phytec-iot/RIOT,binarylemon/RIOT,daniel-k/RIOT,automote/RIOT,msolters/RIOT,jfischer-phytec-iot/RIOT,syin2/RIOT,adrianghc/RIOT,tfar/RIOT,lazytech-org/RIOT,jbeyerstedt/RIOT-OTA-update,rfuentess/RIOT,Yonezawa-T2/RIOT,watr-li/RIOT,asanka-code/RIOT,asanka-code/RIOT,katezilla/RIOT,basilfx/RIOT,katezilla/RIOT,adjih/RIOT,malosek/RIOT,josephnoir/RIOT,rousselk/RIOT,emmanuelsearch/RIOT,RBartz/RIOT,malosek/RIOT,ThanhVic/RIOT,beurdouche/RIOT,MarkXYang/RIOT,EmuxEvans/RIOT,Hyungsin/RIOT-OS,d00616/RIOT,thiagohd/RIOT,gbarnett/RIOT,toonst/RIOT,nsol-nmsu/RIOT,backenklee/RIOT,shady33/RIOT,rfuentess/RIOT,kbumsik/RIOT,nsol-nmsu/RIOT,MonsterCode8000/RIOT,MarkXYang/RIOT,bartfaizoltan/RIOT,ant9000/RIOT,dkm/RIOT,jbeyerstedt/RIOT-OTA-update,wentaoshang/RIOT,thomaseichinger/RIOT,Ell-i/RIOT,Josar/RIOT,brettswann/RIOT,khhhh/RIOT,toonst/RIOT,phiros/RIOT,khhhh/RIOT,JensErdmann/RIOT,attdona/RIOT,mfrey/RIOT,dailab/RIOT,MonsterCode8000/RIOT,wentaoshang/RIOT,MohmadAyman/RIOT,plushvoxel/RIOT,alex1818/RIOT,OlegHahm/RIOT,RBartz/RIOT,kb2ma/RIOT,asanka-code/RIOT,kbumsik/RIOT,chris-wood/RIOT,msolters/RIOT,automote/RIOT,kaleb-himes/RIOT,benoit-canet/RIOT,jasonatran/RIOT,yogo1212/RIOT,Josar/RIOT,miri64/RIOT,jfischer-phytec-iot/RIOT,msolters/RIOT,watr-li/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,koenning/RIOT,smlng/RIOT,ximus/RIOT,MonsterCode8000/RIOT,zhuoshuguo/RIOT,dhruvvyas90/RIOT,immesys/RiSyn,kaleb-himes/RIOT,openkosmosorg/RIOT,kerneltask/RIOT,emmanuelsearch/RIOT,rakendrathapa/RIOT,fnack/RIOT