Rename "[Mm]ethod(s)" to "[Ff]unction(s)"

Only methods as programming functions are affected. Besides renaming
some actions like "Switch Between Function Declaration/Definition" this
mostly touches (api) code comments.

This is a follow-up patch to commit 872bfb7.

Change-Id: Icb65e8d73b59a022f8885b14df497169543a3b92
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/coreplugin/actionmanager/actioncontainer.cpp

@@ -54,7 +54,7 @@ using namespace Core::Internal;
 
     You don't create instances of this class directly, but instead use the
     \l{ActionManager::createMenu()}
-    and \l{ActionManager::createMenuBar()} methods.
+    and \l{ActionManager::createMenuBar()} functions.
     Retrieve existing action containers for an ID with
     \l{ActionManager::actionContainer()}.