git log: invert --author and --committer

We have a repository that mostly contains configuration data.
This is updated by our continuous integration build system, but
every once in a while there are also more interesting commits
made by humans.

For several years I have suffered in silence, wishing for a way
to do something like

    git log --author-not cibot

Today a friend told me that you can actually list all commits
except those made by cibot with this commandline:

    git log --invert-grep --author cibot

The documentation for --invert-grep should mention that it
also inverts the meaning of --author and --committer.  Perphaps
something like this would make sense?

    /ceder

diff --git a/Documentation/rev-list-options.txt

b/Documentation/rev-list-options.txt
index 4f009d4..ae12687 100644

--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt

@@ -70,7 +70,8 @@ endif::git-rev-list[]

 --invert-grep::
  Limit the commits output to ones with log message that do not
- match the pattern specified with `--grep=<pattern>`.
+ match the pattern specified with `--grep=<pattern>`.  Also
+ affects `--author=<pattern>` and `--committer=<pattern>`.

 -i::
 --regexp-ignore-case::