Docs: Explain GitMate review keywords
Docs: Explain GitMate review keywords

- Document the keywords the coala project uses for GitMate review
  processing.

- Provide examples of how to ack/unack commits in pull requests.

damngamerz/coala,refeed/coala,MariosPanag/coala,Shade5/coala,rimacone/testing2,netman92/coala,ayushin78/coala,refeed/coala,yashtrivedi96/coala,ayushin78/coala,abhiroyg/coala,netman92/coala,sils1297/coala,yashLadha/coala,jayvdb/coala,RJ722/coala,MariosPanag/coala,jayvdb/coala,CruiseDevice/coala,vinc456/coala,arjunsinghy96/coala,coala/coala,sagark123/coala,Asalle/coala,coala-analyzer/coala,Shade5/coala,rimacone/testing2,ayushin78/coala,shreyans800755/coala,Balaji2198/coala,Balaji2198/coala,karansingh1559/coala,nemaniarjun/coala,NiklasMM/coala,mr-karan/coala,Asalle/coala,tushar-rishav/coala,MariosPanag/coala,abhiroyg/coala,CruiseDevice/coala,aptrishu/coala,JohnS-01/coala,stevemontana1980/coala,vinc456/coala,incorrectusername/coala,Nosferatul/coala,shreyans800755/coala,CruiseDevice/coala,tushar-rishav/coala,rimacone/testing2,Balaji2198/coala,incorrectusername/coala,nemaniarjun/coala,arush0311/coala,sils1297/coala,ManjiriBirajdar/coala,arjunsinghy96/coala,NiklasMM/coala,arjunsinghy96/coala,Nosferatul/coala,ManjiriBirajdar/coala,damngamerz/coala,yashtrivedi96/coala,jayvdb/coala,arush0311/coala,Shade5/coala,JohnS-01/coala,coala/coala,RJ722/coala,RJ722/coala,shreyans800755/coala,stevemontana1980/coala,netman92/coala,meetmangukiya/coala,meetmangukiya/coala,sils1297/coala,karansingh1559/coala,kartikeys98/coala,sagark123/coala,Asnelchristian/coala,yashLadha/coala,mr-karan/coala,sagark123/coala,mr-karan/coala,nemaniarjun/coala,tushar-rishav/coala,damngamerz/coala,Asalle/coala,arush0311/coala,JohnS-01/coala,abhiroyg/coala,meetmangukiya/coala,incorrectusername/coala,coala-analyzer/coala,aptrishu/coala,aptrishu/coala,impmihai/coala,NiklasMM/coala,stevemontana1980/coala,yashLadha/coala,impmihai/coala,SanketDG/coala,kartikeys98/coala,yashtrivedi96/coala,coala/coala,vinc456/coala,SanketDG/coala,SanketDG/coala,ManjiriBirajdar/coala,Asnelchristian/coala,impmihai/coala,refeed/coala,coala-analyzer/coala,Nosferatul/coala,kartikeys98/coala,Asnelchristian/coala,karansingh1559/coala