[wp-docs] Codex pages directly linked from Help Tabs

[Safirul Alredha]

Appearance > Themes is using http://codex.wordpress.org/Using_Themes
which is outdated and too general. #Adding_New_Themes is now obsolete.

I suggest cleaning Using_Themes (permanently replace to
Appearance_Themes), add
http://codex.wordpress.org/Appearance_Themes_SubPanel#Manage_Themes
for Manage Themes tab and
http://codex.wordpress.org/Appearance_Themes_SubPanel#Install_Themes
for Install Themes tab.

The result:

Appearance
\__ Themes
      \__ Manage Themes
           For more information:
           Documentation on Themes -
http://codex.wordpress.org/Appearance_Themes_SubPanel
           Documentation on Managing Themes
http://codex.wordpress.org/Appearance_Themes_SubPanel#Manage_Themes

      \__ Install Themes
           For more information:
           Documentation on Themes -
http://codex.wordpress.org/Appearance_Themes_SubPanel
           Documentation on Installing Themes
http://codex.wordpress.org/Appearance_Themes_SubPanel#Install_Themes