Fix spelling in comments and documentation using codespell

Apply the utility from https://github.com/codespell-project/codespell/
to fix spelling issues in the headers under both include and interface
directories and add a file with a couple of exceptions.

The exact command line used was:

    $ codespell -w -I misc/scripts/codespell.ignore -i 3 in*

include/wx/msw/menu.h

@@ -136,7 +136,7 @@ private:
     // It is initially NULL and only allocated if we have any radio items.
     wxMenuRadioItemsData *m_radioData;
 
-    // if true, insert a breal before appending the next item
+    // if true, insert a break before appending the next item
     bool m_doBreak;
 
     // the menu handle of this menu