[gnome-characters] window: Add a comment for translator

[Daiki Ueno <dueno src gnome org>]

commit 16160a6ced96a2ce2df0744821e6f8e8497f6e32
Author: Daiki Ueno <dueno src gnome org>
Date:   Thu Aug 24 16:52:27 2017 +0200

    window: Add a comment for translator

 src/window.js |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/window.js b/src/window.js
index 7574e28..12b6914 100644
--- a/src/window.js
+++ b/src/window.js
@@ -354,6 +354,7 @@ const MainView = new Lang.Class({
             }
             characterList = this._createRecentCharacterList(
                 category.name,
+                // TRANSLATORS: %s will be either 'emojis' or 'letters'
                 _('Recently Used %s Character List').format(category.title),
                 category.category);
             this._recentCharacterLists[category.name] = characterList;