Should mention --no-ff in Pull Request section (integrate 10.iv to 4)

[Jaykul]

There is a sort-of footnote in the git best practices section:

vi. It is RECOMMENDED that all branches be merged using "git merge --no-ff". This makes sure the reference to the original branch is kept in the commits, allows one to revert a merge by reverting a single merge commit, and creates a merge commit to mark the integration of the branch with master.

I think this should be moved/copied to section 4 where you're initially discussing merging pull requests and change branches (just as the --force-with-lease is mentioned when rebasing is mentioned). My suggestion would be to insert 10-vi into 4 as a new v (pushing the current v to vi).