[gnome-maps] gschema: Add translator comment about constant strings

[Marcus Lundblad <mlundblad src gnome org>]

commit a0eec5a39ee8cfa00f7f1a8502ff6ab9e9bee546
Author: Marcus Lundblad <ml update uu se>
Date:   Mon Dec 25 22:27:14 2017 +0100

    gschema: Add translator comment about constant strings

 data/org.gnome.Maps.gschema.xml |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/data/org.gnome.Maps.gschema.xml b/data/org.gnome.Maps.gschema.xml
index 9585a45..417fecb 100644
--- a/data/org.gnome.Maps.gschema.xml
+++ b/data/org.gnome.Maps.gschema.xml
@@ -44,6 +44,7 @@
     <key name="checkin-facebook-privacy" type="s">
       <default>"EVERYONE"</default>
       <summary>Facebook check-in privacy setting</summary>
+      <!-- Translators: EVERYONE, FRIENDS_OF_FRIENDS, ALL_FRIENDS, and SELF are constant names, and should 
not be translated -->
       <description>Latest used Facebook check-in privacy setting. Possible values are: EVERYONE, 
FRIENDS_OF_FRIENDS, ALL_FRIENDS or SELF.</description>
     </key>
     <key name="checkin-foursquare-privacy" type="s">