Add a push option to ignore attention set update

We already offer this option in PostReview, so it's good to also offer
it on push, since there are many ways to modify the attention set using
the default rules (add reviewer, make a change wip, etc).

Change-Id: I3c4134bea2b4e88ebb9a45cc41ccf4d23ff4b60c

Documentation/user-upload.txt

diff --git a/Documentation/user-upload.txt b/Documentation/user-upload.txt
index 0670968..a04ff35 100644
--- a/Documentation/user-upload.txt
+++ b/Documentation/user-upload.txt
@@ -622,6 +622,20 @@
 point, which could be slow and create lots of unintended new changes.
 To create multiple new changes, run push multiple times.
 
+[[ignore-attention-set]]
+=== Ignore automatic attention set rules
+
+Normally, we add users to the attention set based on several rules such as adding
+reviewers, replying, and many others. The full rule list is in
+link:user-attention-set.html[Attention Set].
+
+--ignore-automatic-attention-set-rules (also known as -ias and
+-ignore-attention-set) can be used to keep the attention set as it were before
+the push.
+
+----
+  git push ssh://john.doe@git.example.com:29418/kernel/common my-merged-commit:refs/for/master%ias
+----
 
 == repo upload