doc: On the number of commits per PR
doc: On the number of commits per PR

In response to @vais (https://github.com/opal/opal/pull/1180#issuecomment-155060845) :)

[skip ci]
jgaskins/opal,wied03/opal,iliabylich/opal,jgaskins/opal,kachick/opal,Mogztter/opal,opal/opal,kachick/opal,jgaskins/opal,Mogztter/opal,opal/opal,Mogztter/opal,opal/opal,iliabylich/opal,wied03/opal,kachick/opal,Mogztter/opal,wied03/opal,kachick/opal,opal/opal,iliabylich/opal