[gedit-plugins] Improve translator comment for Apertium language pair values

[Andre Klapper <aklapper src gnome org>]

commit d857230b965fac072bb5d3288b592b8defecc8b8
Author: Andre Klapper <a9016009 gmx de>
Date:   Tue May 26 16:50:02 2020 +0200

    Improve translator comment for Apertium language pair values
    
    Fixes #27

 plugins/translate/org.gnome.gedit.plugins.translate.gschema.xml | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/plugins/translate/org.gnome.gedit.plugins.translate.gschema.xml 
b/plugins/translate/org.gnome.gedit.plugins.translate.gschema.xml
index 854ef86..3de4824 100644
--- a/plugins/translate/org.gnome.gedit.plugins.translate.gschema.xml
+++ b/plugins/translate/org.gnome.gedit.plugins.translate.gschema.xml
@@ -9,9 +9,10 @@
     </key>
    <key name="language-pair" type="s">
       <!-- Translators: You can adjust the default pair for users in your locale.
-      http://wiki.apertium.org/wiki/List_of_language_pairs has a list of valid pairs.
-      Remember to keep formatting as-is, or things will break! Use ASCII quotation
-      marks and | as the delimiter. -->
+      https://wiki.apertium.org/wiki/List_of_language_pairs lists valid pairs, in
+      the format apertium-xxx-yyy. For this translation, use ASCII apostrophes and
+      | as the delimiter. Language pair values must be in the format 'xxx|yyy' -
+      You must keep this format 'xxx|yyy', or things will break!  -->
       <default l10n="messages">'eng|spa'</default>
       <summary>Language pair used</summary>
       <description>