Merge branch 'lm/add-p-context'

"git add/etc -p" now honor the diff.context configuration variable,
and also they learn to honor the -U<n> command-line option.

* lm/add-p-context:
  add-patch: add diff.context command line overrides
  add-patch: respect diff.context configuration
  t: use test_config in t4055
  t: use test_grep in t3701 and t4055

Documentation/git-restore.adoc

@@ -50,6 +50,8 @@ leave out at most one of _<rev-A>__ and _<rev-B>_, in which case it defaults to
 	Mode" section of linkgit:git-add[1] to learn how to operate
 	the `--patch` mode.
 
+include::diff-context-options.adoc[]
+
 `-W`::
 `--worktree`::
 `-S`::