[doc] productivity: fix broken link
[doc] productivity: fix broken link

bitcoin/bitcoin,vertcoin/vertcoin,prusnak/bitcoin,ajtowns/bitcoin,prusnak/bitcoin,litecoin-project/litecoin,peercoin/peercoin,cdecker/bitcoin,andreaskern/bitcoin,ahmedbodi/vertcoin,ajtowns/bitcoin,pataquets/namecoin-core,droark/bitcoin,alecalve/bitcoin,mitchellcash/bitcoin,cdecker/bitcoin,anditto/bitcoin,MarcoFalke/bitcoin,Xekyo/bitcoin,peercoin/peercoin,CryptArc/bitcoin,yenliangl/bitcoin,cdecker/bitcoin,FeatherCoin/Feathercoin,fanquake/bitcoin,ahmedbodi/vertcoin,bitcoinknots/bitcoin,bitcoin/bitcoin,MeshCollider/bitcoin,Sjors/bitcoin,fanquake/bitcoin,nikkitan/bitcoin,alecalve/bitcoin,pataquets/namecoin-core,particl/particl-core,monacoinproject/monacoin,qtumproject/qtum,nikkitan/bitcoin,apoelstra/bitcoin,afk11/bitcoin,droark/bitcoin,monacoinproject/monacoin,gjhiggins/vcoincore,vertcoin/vertcoin,CryptArc/bitcoin,tjps/bitcoin,jonasschnelli/bitcoin,MeshCollider/bitcoin,jtimon/bitcoin,bitcoinknots/bitcoin,achow101/bitcoin,n1bor/bitcoin,namecoin/namecore,yenliangl/bitcoin,rnicoll/bitcoin,rnicoll/bitcoin,practicalswift/bitcoin,jambolo/bitcoin,jambolo/bitcoin,tecnovert/particl-core,DigitalPandacoin/pandacoin,pstratem/bitcoin,sipsorcery/bitcoin,AkioNak/bitcoin,prusnak/bitcoin,namecoin/namecoin-core,qtumproject/qtum,lateminer/bitcoin,rnicoll/dogecoin,nikkitan/bitcoin,yenliangl/bitcoin,Xekyo/bitcoin,bitcoinknots/bitcoin,namecoin/namecore,yenliangl/bitcoin,practicalswift/bitcoin,fujicoin/fujicoin,vertcoin/vertcoin,JeremyRubin/bitcoin,bitcoinknots/bitcoin,litecoin-project/litecoin,sstone/bitcoin,GroestlCoin/bitcoin,lateminer/bitcoin,cdecker/bitcoin,monacoinproject/monacoin,lateminer/bitcoin,jlopp/statoshi,peercoin/peercoin,gjhiggins/vcoincore,rnicoll/dogecoin,tjps/bitcoin,jnewbery/bitcoin,jonasschnelli/bitcoin,particl/particl-core,practicalswift/bitcoin,AkioNak/bitcoin,namecoin/namecore,GroestlCoin/bitcoin,r8921039/bitcoin,bitcoinsSG/bitcoin,midnightmagic/bitcoin,Xekyo/bitcoin,apoelstra/bitcoin,ahmedbodi/vertcoin,lateminer/bitcoin,tjps/bitcoin,ElementsProject/elements,pstratem/bitcoin,practicalswift/bitcoin,n1bor/bitcoin,pataquets/namecoin-core,droark/bitcoin,GroestlCoin/GroestlCoin,mm-s/bitcoin,domob1812/namecore,litecoin-project/litecoin,JeremyRubin/bitcoin,Xekyo/bitcoin,alecalve/bitcoin,qtumproject/qtum,MeshCollider/bitcoin,bitcoinknots/bitcoin,pstratem/bitcoin,afk11/bitcoin,JeremyRubin/bitcoin,midnightmagic/bitcoin,kallewoof/bitcoin,bitcoinsSG/bitcoin,achow101/bitcoin,FeatherCoin/Feathercoin,pstratem/bitcoin,namecoin/namecoin-core,DigitalPandacoin/pandacoin,namecoin/namecoin-core,anditto/bitcoin,EthanHeilman/bitcoin,tjps/bitcoin,DigitalPandacoin/pandacoin,domob1812/namecore,pstratem/bitcoin,sstone/bitcoin,particl/particl-core,tecnovert/particl-core,andreaskern/bitcoin,ElementsProject/elements,rnicoll/dogecoin,dscotese/bitcoin,afk11/bitcoin,dscotese/bitcoin,kallewoof/bitcoin,GroestlCoin/GroestlCoin,monacoinproject/monacoin,jamesob/bitcoin,MarcoFalke/bitcoin,r8921039/bitcoin,mm-s/bitcoin,gjhiggins/vcoincore,jnewbery/bitcoin,tecnovert/particl-core,Xekyo/bitcoin,prusnak/bitcoin,domob1812/bitcoin,jnewbery/bitcoin,ahmedbodi/vertcoin,qtumproject/qtum,MeshCollider/bitcoin,fanquake/bitcoin,domob1812/bitcoin,dscotese/bitcoin,afk11/bitcoin,instagibbs/bitcoin,CryptArc/bitcoin,jtimon/bitcoin,AkioNak/bitcoin,jambolo/bitcoin,practicalswift/bitcoin,FeatherCoin/Feathercoin,sstone/bitcoin,droark/bitcoin,namecoin/namecoin-core,dscotese/bitcoin,MarcoFalke/bitcoin,mm-s/bitcoin,jlopp/statoshi,tecnovert/particl-core,wellenreiter01/Feathercoin,particl/particl-core,n1bor/bitcoin,ahmedbodi/vertcoin,MarcoFalke/bitcoin,ElementsProject/elements,ahmedbodi/vertcoin,instagibbs/bitcoin,sipsorcery/bitcoin,GroestlCoin/GroestlCoin,ajtowns/bitcoin,tecnovert/particl-core,dscotese/bitcoin,jonasschnelli/bitcoin,yenliangl/bitcoin,droark/bitcoin,mruddy/bitcoin,dscotese/bitcoin,EthanHeilman/bitcoin,jamesob/bitcoin,achow101/bitcoin,anditto/bitcoin,cdecker/bitcoin,ajtowns/bitcoin,CryptArc/bitcoin,GroestlCoin/GroestlCoin,EthanHeilman/bitcoin,andreaskern/bitcoin,bitcoinsSG/bitcoin,litecoin-project/litecoin,n1bor/bitcoin,litecoin-project/litecoin,achow101/bitcoin,kallewoof/bitcoin,fanquake/bitcoin,mitchellcash/bitcoin,jambolo/bitcoin,kallewoof/bitcoin,DigitalPandacoin/pandacoin,apoelstra/bitcoin,apoelstra/bitcoin,vertcoin/vertcoin,GroestlCoin/bitcoin,achow101/bitcoin,domob1812/namecore,alecalve/bitcoin,mm-s/bitcoin,GroestlCoin/bitcoin,sipsorcery/bitcoin,pataquets/namecoin-core,practicalswift/bitcoin,domob1812/namecore,particl/particl-core,jtimon/bitcoin,Sjors/bitcoin,AkioNak/bitcoin,mitchellcash/bitcoin,nikkitan/bitcoin,alecalve/bitcoin,tjps/bitcoin,r8921039/bitcoin,rnicoll/bitcoin,bitcoin/bitcoin,tjps/bitcoin,midnightmagic/bitcoin,domob1812/bitcoin,GroestlCoin/bitcoin,ElementsProject/elements,pataquets/namecoin-core,wellenreiter01/Feathercoin,midnightmagic/bitcoin,andreaskern/bitcoin,namecoin/namecore,mruddy/bitcoin,fujicoin/fujicoin,tecnovert/particl-core,andreaskern/bitcoin,JeremyRubin/bitcoin,jtimon/bitcoin,mitchellcash/bitcoin,EthanHeilman/bitcoin,ajtowns/bitcoin,jamesob/bitcoin,kallewoof/bitcoin,jonasschnelli/bitcoin,jambolo/bitcoin,cdecker/bitcoin,namecoin/namecoin-core,FeatherCoin/Feathercoin,qtumproject/qtum,nikkitan/bitcoin,fujicoin/fujicoin,rnicoll/bitcoin,jnewbery/bitcoin,r8921039/bitcoin,kallewoof/bitcoin,GroestlCoin/GroestlCoin,ajtowns/bitcoin,JeremyRubin/bitcoin,gjhiggins/vcoincore,sstone/bitcoin,mitchellcash/bitcoin,domob1812/bitcoin,bitcoinsSG/bitcoin,litecoin-project/litecoin,fujicoin/fujicoin,domob1812/bitcoin,jnewbery/bitcoin,yenliangl/bitcoin,domob1812/namecore,pstratem/bitcoin,sstone/bitcoin,fanquake/bitcoin,mruddy/bitcoin,monacoinproject/monacoin,instagibbs/bitcoin,qtumproject/qtum,jonasschnelli/bitcoin,jlopp/statoshi,rnicoll/dogecoin,jambolo/bitcoin,peercoin/peercoin,alecalve/bitcoin,rnicoll/bitcoin,bitcoin/bitcoin,namecoin/namecore,gjhiggins/vcoincore,jlopp/statoshi,jamesob/bitcoin,sipsorcery/bitcoin,r8921039/bitcoin,anditto/bitcoin,fanquake/bitcoin,lateminer/bitcoin,r8921039/bitcoin,fujicoin/fujicoin,anditto/bitcoin,CryptArc/bitcoin,afk11/bitcoin,MeshCollider/bitcoin,ElementsProject/elements,Sjors/bitcoin,AkioNak/bitcoin,Sjors/bitcoin,wellenreiter01/Feathercoin,peercoin/peercoin,jtimon/bitcoin,particl/particl-core,lateminer/bitcoin,bitcoin/bitcoin,sstone/bitcoin,andreaskern/bitcoin,wellenreiter01/Feathercoin,bitcoinsSG/bitcoin,jlopp/statoshi,mruddy/bitcoin,instagibbs/bitcoin,CryptArc/bitcoin,MarcoFalke/bitcoin,midnightmagic/bitcoin,Xekyo/bitcoin,droark/bitcoin,monacoinproject/monacoin,namecoin/namecore,vertcoin/vertcoin,sipsorcery/bitcoin,sipsorcery/bitcoin,rnicoll/bitcoin,gjhiggins/vcoincore,peercoin/peercoin,apoelstra/bitcoin,GroestlCoin/GroestlCoin,GroestlCoin/bitcoin,mm-s/bitcoin,MarcoFalke/bitcoin,AkioNak/bitcoin,MeshCollider/bitcoin,pataquets/namecoin-core,midnightmagic/bitcoin,n1bor/bitcoin,FeatherCoin/Feathercoin,anditto/bitcoin,jtimon/bitcoin,rnicoll/dogecoin,n1bor/bitcoin,instagibbs/bitcoin,apoelstra/bitcoin,EthanHeilman/bitcoin,fujicoin/fujicoin,Sjors/bitcoin,FeatherCoin/Feathercoin,namecoin/namecoin-core,JeremyRubin/bitcoin,bitcoinsSG/bitcoin,domob1812/namecore,DigitalPandacoin/pandacoin,jlopp/statoshi,mruddy/bitcoin,mm-s/bitcoin,mruddy/bitcoin,achow101/bitcoin,instagibbs/bitcoin,wellenreiter01/Feathercoin,EthanHeilman/bitcoin,bitcoin/bitcoin,prusnak/bitcoin,qtumproject/qtum,vertcoin/vertcoin,domob1812/bitcoin,afk11/bitcoin,DigitalPandacoin/pandacoin,prusnak/bitcoin,nikkitan/bitcoin,jamesob/bitcoin,ElementsProject/elements,wellenreiter01/Feathercoin,jamesob/bitcoin,mitchellcash/bitcoin