Update RELEASE-CHECKLIST with a few minor nits (periods, whitespace)

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)

hack/RELEASE-CHECKLIST.md

@@ -34,11 +34,12 @@ git checkout --track origin/release
 git checkout -b bump_$VERSION
 ```
 
-If it's a regular release, we usually merge master
+If it's a regular release, we usually merge master.
 ```bash
 git merge origin/master
 ```
-Otherwise, if it is a hotfix release, we cherry-pick only the commits we want
+
+Otherwise, if it is a hotfix release, we cherry-pick only the commits we want.
 ```bash
 # get the commits ids we want to cherry-pick
 git log