doc/emacs: document notmuch-show-toggle-toggle-elide-non-matching

Recently there was a question on the mailing list about the existence
of this function, so let us try to make it more discoverable.

diff --git a/doc/notmuch-emacs.rst b/doc/notmuch-emacs.rst
index 41f62390b79c8dee4590eadba30f2ffca5dc32ea..67dbfc2bf3b135b7c070c314e5e946f17da244ec 100644 (file)
--- a/doc/notmuch-emacs.rst
+++ b/doc/notmuch-emacs.rst
@@ -221,6 +221,9 @@ pressing RET after positioning the cursor on a hidden part.
 ``+,-``
     Add or remove arbitrary tags from the current message.
 
+``!``
+    |docstring::notmuch-show-toggle-elide-non-matching|
+
 ``?``
     Display full set of key bindings