hgext/extdiff.py

--- a/hgext/extdiff.py	Wed Jul 27 21:40:42 2016 +0900
+++ b/hgext/extdiff.py	Wed Jul 27 21:42:24 2016 +0900
@@ -385,3 +385,6 @@
                 cmdline += ' ' + args
         command(cmd, extdiffopts[:], _('hg %s [OPTION]... [FILE]...') % cmd,
                 inferrepo=True)(savedcmd(path, cmdline))
+
+# tell hggettext to extract docstrings from these functions:
+i18nfunctions = [savedcmd]