Git_Basics.rst: Change commit body limit to 72
Git_Basics.rst: Change commit body limit to 72

Closes https://github.com/coala/coala/issues/5777

coala/coala,jayvdb/coala,coala/coala,jayvdb/coala,jayvdb/coala,coala-analyzer/coala,coala-analyzer/coala,SanketDG/coala,SanketDG/coala,SanketDG/coala,coala/coala,coala-analyzer/coala