[gnome-characters] character: Add a comment for translators

[Piotr Drąg <piotrdrag src gnome org>]

commit 85c9fe411b15ba370dad8761af946218016ffc72
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Wed Dec 16 01:24:43 2015 +0100

    character: Add a comment for translators

 src/character.js |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/character.js b/src/character.js
index 8b0451a..1ba985d 100644
--- a/src/character.js
+++ b/src/character.js
@@ -131,6 +131,7 @@ const CharacterDialog = new Lang.Class({
         } else {
             var fontFamily = this._fontDescription.get_family();
             this._missing_label.label =
+                // TRANSLATORS: the first variable is a character, the second is a font
                 _("%s is not included in %s").format(name, fontFamily);
             this._character_stack.visible_child_name = 'missing';
         }