Improve naming consistency

[banesullivan]

Resolve #429 to improve naming consistency for *_scalars and *_array. This should be good to go and has deprecation warnings for the old methods to keep backward compatibility.

@pyvista/developers, anyone have time to double-check all of this? This needs to land before the 0.23.0 release.

[imsodin]

In many docstrings and comments it's still scalar, not scalars, that's used. That's definitely minor, but somewhat inconsistent. Maybe worth running sed -e 's/ scalar / scalars /' over it.

[banesullivan]

@imsodin, thanks for the review! And thanks for catching my sloppy copy/paste errors - that's what happens when I work on this stuff late at night

[banesullivan]

In many docstrings and comments it's still scalar, not scalars, that's used.

@imsodin, I just committed a change that updates the docstrings use of scalar to either scalars or array depending on the context

[imsodin]

@imsodin, thanks for the review! And thanks for catching my sloppy copy/paste errors - that's what happens when I work on this stuff late at night

I hope you don't take my remarks as criticism - I would be surprised if there wasn't any ;)

I am approving this, but I only skimmed (briefly) through it. However I think any remaining issues should be cosmetic and more reviewer time is better spent on functional stuff.

[banesullivan]

I hope you don't take my remarks as criticism - I would be surprised if there wasn't any ;)

Oh, I definitely don't - your feedback is much appreciated! I am awful at catching my own mistakes these days.

I am approving this, but I only skimmed (briefly) through it. However I think any remaining issues should be cosmetic and more reviewer time is better spent on functional stuff.

Fair - I think all is good at this point. @GuillaumeFavelier, it would be great to have your eyes on this and perhaps use this PR as a place to implement to the decorator in #469