__init__.py: Add help description
__init__.py: Add help description

There is no description of coalib provided in its help documentation.
Thus this will take care of it.

Closes https://github.com/coala/coala/issues/1663

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