Necessary because the CppHoverHandler uses QtHelp and moved from
CppTools to CppEditor.

It used to be in CppTools, but since the hover handler only makes sense
in the context of the C++ editor, this is a better place.

It is now possible to choose between case-sensitive or case-insensitive
completion. Also, you can now disable the automatic insertion of braces.

To match the class name, CppToolsPlugin.

In the GUI this is currently called "Methods" with the shortcut 'm'.

Invokable with 'c', currently shows all classes it can find.