[dia] Add a translator comment to the desktop file

[Piotr Drąg <piotrdrag src gnome org>]

commit f32d877136679dd898ba0996e2b932ddcaeed5c7
Author: Piotr Drąg <piotrdrag gmail com>
Date:   Sun May 26 18:25:23 2019 +0200

    Add a translator comment to the desktop file
    
    It will make Damned Lies skip extracting Icon when generating .po files.

 data/dia.desktop | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/data/dia.desktop b/data/dia.desktop
index 1847b4a4..dcdf9a22 100644
--- a/data/dia.desktop
+++ b/data/dia.desktop
@@ -4,6 +4,7 @@ GenericName=Diagram Editor
 Comment=Edit your Diagrams
 Type=Application
 Exec=dia %F
+# Translators: Do NOT translate or transliterate this text (this is an icon file name)!
 Icon=dia
 Terminal=false
 Categories=GNOME;Graphics;