Writing_Linter_Bears: Add unified-diff
Writing_Linter_Bears: Add unified-diff

Add documentation for unified-diff output
format.

Closes https://github.com/coala/coala/issues/3733

rimacone/testing2,Shade5/coala,Balaji2198/coala,rimacone/testing2,CruiseDevice/coala,MariosPanag/coala,shreyans800755/coala,shreyans800755/coala,yashLadha/coala,Asnelchristian/coala,netman92/coala,Nosferatul/coala,coala-analyzer/coala,RJ722/coala,JohnS-01/coala,kartikeys98/coala,kartikeys98/coala,arjunsinghy96/coala,JohnS-01/coala,CruiseDevice/coala,jayvdb/coala,jayvdb/coala,netman92/coala,RJ722/coala,coala/coala,Balaji2198/coala,coala/coala,damngamerz/coala,nemaniarjun/coala,damngamerz/coala,CruiseDevice/coala,Nosferatul/coala,Asnelchristian/coala,SanketDG/coala,kartikeys98/coala,RJ722/coala,karansingh1559/coala,incorrectusername/coala,coala/coala,arjunsinghy96/coala,Asnelchristian/coala,Shade5/coala,damngamerz/coala,yashLadha/coala,Nosferatul/coala,refeed/coala,incorrectusername/coala,Asalle/coala,nemaniarjun/coala,coala-analyzer/coala,JohnS-01/coala,Shade5/coala,MariosPanag/coala,MariosPanag/coala,refeed/coala,jayvdb/coala,shreyans800755/coala,arjunsinghy96/coala,karansingh1559/coala,refeed/coala,yashLadha/coala,SanketDG/coala,Asalle/coala,incorrectusername/coala,SanketDG/coala,netman92/coala,rimacone/testing2,nemaniarjun/coala,Asalle/coala,aptrishu/coala,aptrishu/coala,coala-analyzer/coala,aptrishu/coala,karansingh1559/coala,Balaji2198/coala