Update repo commits api to use new helper methods, modify docs.
Update repo commits api to use new helper methods, modify docs.

firstval/github,durai145/github,befairyliu/github,davengeo/github,wicky-info/github,samphilipd/github,GistBox/github,anabhilash619/github,MalachiTatum/github,peter-murach/github,piotrmurach/github,cocktail-io/github,yaoxiaoyong/github,joshsoftware/github