Fix: sourceCode#isSpaceBetweenTokens() checks non-adjacent tokens

[kaicataldo]

What is the purpose of this pull request? (put an "X" next to item)

[ ] Documentation update
[x] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

What changes did you make? (Give an overview)

I noticed that sourceCode#isSpaceBetweenTokens() assumes that the given arguments are tokens and that they are adjacent, but there is nothing stopping a consumer from using non-adjacent tokens as well as AST nodes (example here).

I think it would make sense to only allow tokens that are adjacent as arguments, however, that would be a breaking change. This PR updates the logic so that it will check for any whitespace between tokens (including comments) between two given nodes or tokens. The only difference in behavior is the following two tests (two tokens with a string containing spaces between them is currently incorrectly being flagged as containing whitespace):

// Both of the following should return false but currently return true.

a/* */+' /**/ '/* */+c

a/* */+` /*
*/ `/* */+c

The rest of the tests cover the current behavior that already exists.

Is there anything you'd like reviewers to focus on?

Does this seem like the correct solution to the rest of the team?

[kaicataldo]

On further reflection, I think that it would make sense to rename this method to isSpaceBetween() and leave the ability for it to check between nodes and tokens, as that's a useful behavior that is most likely being used by custom rules (since we use it in at least one of our core rules). We could deprecate isSpaceBetweenTokens() and leave it as an alias that calls through to isSpaceBetween() for the sake of backwards compatibility.

Would it make sense to make an RFC for this or just flag this for TSC discussion? Just to reiterate, the only change in behavior are the examples described above. Aside from that bug fix, this is adding tests and documentation for existing behavior.

[platinumazure]

I think a simple TSC decision would be sufficient, personally.

[kaicataldo]

TSC Summary

While fixing a bug in in sourceCode#isSpaceBetweenTokens(), I noticed that the current documentation is incorrect, also making the name of the method not quite correct.

TSC Question

In addition to the bug fix/documentation corrections, I'd like to propose we deprecate sourceCode#isSpaceBetweenTokens() to in favor of sourceCode#isSpaceBetween(). This more accurately describes the behavior, as the method currently will check between nodes as well as tokens, and better matches the names of other sourceCode methods that check between nodes or tokens.

This PR currently deprecates sourceCode#isSpaceBetweenTokens() in a backwards compatible way, having it call through to the new method.

EDIT: Please see #12519 for this proposal. This PR is now just the bug fix.

[kaicataldo]

I'm actually going to split this out into two separate PRs - one for the bug fix and one for the deprecation proposal.

[kaicataldo]

New PR added here.

[mysticatea]

LGTM, thank you!