gnrc_neterr: move doxygen group into GNRC group
gnrc_neterr: move doxygen group into GNRC group

ant9000/RIOT,rfuentess/RIOT,rfuentess/RIOT,authmillenon/RIOT,mtausig/RIOT,authmillenon/RIOT,x3ro/RIOT,aeneby/RIOT,x3ro/RIOT,RIOT-OS/RIOT,x3ro/RIOT,mtausig/RIOT,toonst/RIOT,aeneby/RIOT,yogo1212/RIOT,toonst/RIOT,kYc0o/RIOT,rfuentess/RIOT,smlng/RIOT,kaspar030/RIOT,mfrey/RIOT,miri64/RIOT,kYc0o/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,x3ro/RIOT,kYc0o/RIOT,OTAkeys/RIOT,smlng/RIOT,OlegHahm/RIOT,rfuentess/RIOT,kYc0o/RIOT,x3ro/RIOT,toonst/RIOT,josephnoir/RIOT,cladmi/RIOT,ant9000/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,miri64/RIOT,josephnoir/RIOT,basilfx/RIOT,OTAkeys/RIOT,authmillenon/RIOT,OTAkeys/RIOT,aeneby/RIOT,basilfx/RIOT,jasonatran/RIOT,smlng/RIOT,josephnoir/RIOT,ant9000/RIOT,basilfx/RIOT,OlegHahm/RIOT,mfrey/RIOT,yogo1212/RIOT,OTAkeys/RIOT,jasonatran/RIOT,miri64/RIOT,RIOT-OS/RIOT,mtausig/RIOT,yogo1212/RIOT,ant9000/RIOT,kaspar030/RIOT,mfrey/RIOT,authmillenon/RIOT,cladmi/RIOT,cladmi/RIOT,OTAkeys/RIOT,jasonatran/RIOT,aeneby/RIOT,jasonatran/RIOT,smlng/RIOT,kaspar030/RIOT,kaspar030/RIOT,authmillenon/RIOT,mfrey/RIOT,kYc0o/RIOT,yogo1212/RIOT,ant9000/RIOT,RIOT-OS/RIOT,cladmi/RIOT,aeneby/RIOT,yogo1212/RIOT,mfrey/RIOT,basilfx/RIOT,miri64/RIOT,OlegHahm/RIOT,josephnoir/RIOT,mtausig/RIOT,OlegHahm/RIOT,miri64/RIOT,basilfx/RIOT,toonst/RIOT,rfuentess/RIOT,smlng/RIOT,josephnoir/RIOT,authmillenon/RIOT,yogo1212/RIOT,cladmi/RIOT,mtausig/RIOT,toonst/RIOT