git-shortlog.txt: include commit limiting options

git-shortlog.txt: include commit limiting options

git-shortlog, like git-log, supports options to filter what commits are
used to generate the log. These options come from git-rev-list, and are
documented in Documentation/rev-list-options.txt. Include those options
in shortlog's documentation.

But since rev-list-options.txt contains some other options that don't
really apply in the context of shortlog (like diff formatting, commit
ordering, etc), add a switch in rev-list-options.txt that excludes those
sections from the shortlog documentation. To be more specific, include
only the "Commit Limiting" and "History Simplification" sections.

Signed-off-by: Pratyush Yadav <redacted>
Signed-off-by: Junio C Hamano <redacted>