Fix processing of events for MRU entries #10 and more in docview.

Fix processing of events for MRU entries #10 and more in docview.

We only handled events for wxID_FILE1..wxID_FILE9 range but there can be more
than 9 entries in the MRU list. Handle events for as many of them as there are
correctly.

This required adding a fallback handler for all menu events and checking if
the id of the menu item is in the MRU range inside it. Also move this to
wxDocManager itself from wxDocParentFrameAnyBase as it's common for all kinds
of frames anyhow.

Closes #12141.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64569 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775