Minor code cleanup:

- CONTIBUTING.md:20 gives off a warning in Eclipse: "Cannot resolve element with id 'new-features--api-additions'" WikiText Markup Problem
(this is likely a bug in Eclipse since it treats the link in line 20 as an error, but exactly the same link in line 49 is not).
https://github.com/eclipse-platform/eclipse.platform/issues/1799


Spelling Errors in the code:

- propogated
- Hueristic2D

TextFieldBehavior.TextInputTypes seems to be unused (though referenced from Window/TKStage in a comment from what looks like unused methods)

MenuBar:171 unnecessary field:
    private String BIND_MSG =
        "cannot uni-directionally bind to the system menu bar - use bindBidrectional instead";

fix formatting in RegionShim