[gnome-builder] gsettings: add a translator comment

[Piotr Drąg <piotrdrag src gnome org>]

commit 0e20869384704ee84f2c6c63c5c10990c5c1bf49
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Sat Jan 27 01:50:27 2018 +0100

    gsettings: add a translator comment
    
    Related to #341

 data/gsettings/org.gnome.builder.gschema.xml | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/data/gsettings/org.gnome.builder.gschema.xml b/data/gsettings/org.gnome.builder.gschema.xml
index 336db41c6..1cc69e2c2 100644
--- a/data/gsettings/org.gnome.builder.gschema.xml
+++ b/data/gsettings/org.gnome.builder.gschema.xml
@@ -26,6 +26,9 @@
       <description>Use GNOME night light setting to activate night-mode.</description>
     </key>
     <key name="projects-directory" type="s">
+      <!-- Translators: This is the default directory name for user’s
+           projects. Do NOT change the ASCII double quotes ("") to your
+           language’s convention, e.g. do not use “” or »«.-->
       <default l10n="messages">"Projects"</default>
       <summary>Projects directory</summary>
       <description>Directory for all Builder projects.</description>