Update: add support for JSXFragments in indent rule (fixes #12208)

[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:

fixes #12208

What changes did you make? (Give an overview)
This PR adds support to the indent rule for JSX Fragments, which are currently ignored. While working on this, I noticed that comments inside both JSX Element and Fragment tags are ignored if they match the indentation level of either the opening or closing tag delimiter. I've added tests to indicate that this is the desired behavior, but I'm thinking of proposing always indenting those comments one level because I can't foresee an instance when it would refer to anything outside the tag delimiters.

Is there anything you'd like reviewers to focus on?
I believe this matches the behavior of JSX Elements, but would love it if others can help me confirm!

It looks like both Babel's parser and Espree parse the following:

<>
< /* Comment */ 
    / 
/* Comment */ >

Does that seem correct? If so, I can add some tests.

[kaicataldo]

I believe this should be treated as a semver-minor bugfix and have updated the commit message to reflect that.

[platinumazure]

LGTM, thanks!

[mysticatea]

This looks a breaking change. I know several styles about the indentation of tag parts (e.g., the location of > sign).

[kaicataldo]

This PR does increase errors, but it seems like a bug that Fragments aren’t treated the same way as other JSX tags.

[kaicataldo]

@mysticatea Are you against releasing this in a non-major release? I personally would argue that this is a semver-minor bug because it feels like an unintentional oversight that the rule doesn't check JSXFragments, and that it just wasn't updated when JSXFragments were added to the JSX spec.

[mysticatea]

Oh, sorry for my slow response. I had misunderstood because I had not noticed that the indent rule has supported JSX by default. I'm fine with a minor version.

[kaicataldo]

No worries! Thanks for clarifying 😄