Improved Rhelp for Model Menu Dialogs

[derekagorhom]

fixes #8160
replaces #8165

I have updated this branch with the changes done on PR #8159 added the Rhelp dropdown to the Use Model keyboard, Hypothesis Tests, Fit Model and Prepare > Column: Numeric > Enter dialogue.

@N-thony , @rdstern this PR is ready for review.

[rdstern]

@derekagorhom well done. This works really nicely now.
@lloyddewit I hope the code is ok, and if so it could be merged soon?
@ChrisMarsh82 if it is merged, and you are doing another build, then it would be good to include this. It fixes a couple of small errors in the Model Keyboard dialogue. But it isn't worth making a special effort for this. I'd be delighted if anyone used this dialogue sufficiently to find these problems. Maybe worth a small prize. So no harm if it waits for the March release.

[lloyddewit]

@derekagorhom Thanks for the PR, looks good, just a few comments

[derekagorhom]

@lloyddewit i have made all the changes except the one related the clsHelp function on dlgEnter.
can you have a look.
Thanks

[lloyddewit]

@lloyddewit i have made all the changes except the one related the clsHelp function on dlgEnter. can you have a look. Thanks

@derekagorhom thanks, just open comment above.

[lloyddewit]

@derekagorhom thank you, looks good, happy to approve.

@rdstern there are some small changes since your last approval. If you can test/approve, then we can merge, thanks

[rdstern]

Looks fine