Rename File tree in Plugin Manager settings window to Documents
Rename File tree in Plugin Manager settings window to Documents

With http://marc.info/?l=kde-commits&m=131428430807601&w=2 the plugin "Tree View" was renamed to "Documents"
But in the Plugin Manager settings window it is still named "File Tree" not "Documents" as in other places in the GUI.
REVIEW:127721

jfmcarreira/kate,jfmcarreira/kate,jfmcarreira/kate