[doc] Add some tips about GitHub PR refs (#6289)
[doc] Add some tips about GitHub PR refs (#6289)


Frenzie/koreader,Markismus/koreader,poire-z/koreader,Hzj-jie/koreader,poire-z/koreader,pazos/koreader,NiLuJe/koreader,NiLuJe/koreader,koreader/koreader,mwoz123/koreader,koreader/koreader,Frenzie/koreader