Merge branch 'jn/glossary-revision'

The wording for "revision" in the glossary wanted to say it refers
to "commit (noun) as a concept" but it was badly phrased.

This may need further updates to hint that in contexts where it is
clear, the word may refer to an object name, not necessarily a
commit. But the patch as-is is already an improvement.

* jn/glossary-revision:
glossary: a revision is just a commit

diff --cc Documentation/glossary-content.txt
Simple merge