[PATCH 2 of 6] help: document about "bookmarks" template keywords

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1538573538 -32400
#      Wed Oct 03 22:32:18 2018 +0900
# Node ID 6d44024b584d8e8c35d693eddd87e368aa8ea3dd
# Parent  79f940d8a9daa1ad391d5bc9cc1c19be37e6a484
help: document about "bookmarks" template keywords

diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -954,6 +954,14 @@ def bookmark(ui, repo, *names, **opts):
 
     .. container:: verbose
 
+      Template:
+
+      The following keywords are supported in addition to the common template
+      keywords and functions such as ``{bookmark}``. See also
+      :hg:`help templates`.
+
+      :active:  Boolean. True if the bookmark is active.
+
       Examples:
 
       - create an active bookmark for a new line of development::