Build(devscripts): Update RELEASE-CHECKLIST

Mark branches with apostrophes.

[skip ci]

devscripts/RELEASE-CHECKLIST

@@ -21,14 +21,14 @@
 3. Generate new docs using devscripts/build-all-docs. Upload docs using
    devscripts/publish-docs.
 
-4. Run devscripts/postrelease. The script checks out master and null-merge
-   maint. The script restores ANNOUNCE.rst from the previous commit
-   (HEAD~). It calls editor; update next version, remove the list of
+4. Run devscripts/postrelease. The script checks out 'master' and
+   null-merge 'maint'. The script restores ANNOUNCE.rst from the previous
+   commit (HEAD~). It calls editor; update next version, remove the list of
    contributors and the list of changes, edit download URL in ANNOUNCE.rst.
    Edit docs/news.rst - add new version. Edit Version.py and README.rst -
    fix versions. Edit section [egg_info] in setup.cfg. In SetupConfig.py
    edit "Development Status" in trove classifiers; edit dev_tag or download
-   URL. Commit. Verify. Fast-forward next to master.
+   URL. Commit. Verify. Fast-forward 'next' to 'master'.
 
 5. Send announcement to the Cheetah mailing list. For a stable release send
    announcements to python and python-announce mailing lists.