feat: add declaration loc to message in block-scoped-var

[mdjermanovic]

Prerequisites checklist

• I have read the contributing guidelines.

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

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

Fixes #17244

What changes did you make? (Give an overview)

In the block-scoped-var rule, I added the location info of declarations to reported messages. This should clarify cases where there are multiple errors on the same reference, and seems useful in general.

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

[fasttime]

Thanks for this PR! I would suggest to add a test with at least 3 redeclarations of a variable in different blocks, for example:

if (foo) {
    var a = 1;
} else if (bar) {
    var a = 2;
} else {
    var a = 3;
}

This would let us verify the case of two (or more) messages with the same line and column but different data.

In the current implementation, when $n \geq 1$ blocks in a scope declare the same variable, the rule will report $n\times(n - 1)$ problems. I think that this unexpectedly large number or messages (and the fact that they all contained the same text!) is the reason for the confusion in the linked issue #17244.

[mdjermanovic]

if (foo) {
    var a = 1;
} else if (bar) {
    var a = 2;
} else {
    var a = 3;
}

I added this test in e85f274, thanks for the suggestion!

[fasttime]

LGTM.

[snitin315]

LGTM. Thanks!

Can we merge PRs or do we need to hold PRs until we finish #17225?

[mdjermanovic]

Can we merge PRs or do we need to hold PRs until we finish #17225?

We can merge all PRs now, only it would be best to avoid merging those that could cause merge conflicts with tasks from #17225.