[recipes] Make page validate by adding missing <title> tag

[Andre Klapper <aklapper src gnome org>]

commit aa7dd332d067f8468b69b0a5b08e421d09eb444e
Author: Andre Klapper <a9016009 gmx de>
Date:   Sun Sep 17 14:51:49 2017 +0200

    Make page validate by adding missing <title> tag

 help/C/common-problems.page |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/help/C/common-problems.page b/help/C/common-problems.page
index 71106d7..8dc13b5 100644
--- a/help/C/common-problems.page
+++ b/help/C/common-problems.page
@@ -16,6 +16,8 @@
     </license>
   </info>
 
+  <title>Common Problems</title>
+
   <section id="edit-recipes">
   <title>Editing Your Recipes</title>
     <p>If you have change the login or user ID you use to log into your computer,