[gnome-user-docs] Add section about GNOME Characters

[Marek Černocký <mcernocky src gnome org>]

commit db31b562bdbdf75b2c8f7ca7cd6123fd25d9b077
Author: Marek Černocký <marek manet cz>
Date:   Thu Jan 21 20:28:53 2016 +0100

    Add section about GNOME Characters

 gnome-help/C/tips-specialchars.page |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/gnome-help/C/tips-specialchars.page b/gnome-help/C/tips-specialchars.page
index 95f88b3..653172a 100644
--- a/gnome-help/C/tips-specialchars.page
+++ b/gnome-help/C/tips-specialchars.page
@@ -50,6 +50,18 @@
 
   </section>
 
+  <section id="characters">
+    <title>Characters</title>
+    <p>Another useful application shipped with GNOME is <app>Characters</app>.
+    It lets you find and insert unusual characters by browsing character
+    categories or searching for keywords.</p>
+
+    <p>You can launch Characters from the Activities overview. For more
+    information on Characters, see the <link href="help:gnome-characters">
+    Characters Manual</link>.</p>
+
+  </section>
+
   <section id="compose">
     <title>Compose key</title>
     <p>A compose key is a special key that allows you to press multiple keys