Emmet reduce JSX array noise

[rzhao271]

This PR fixes #138461

I thought that we'd have to do a large refactor first, but I realized there's a much simpler mitigation that I can push in instead.

The mitigation disallows completions to show up in JS and JSX files for cases where the abbreviation contains [] characters without a = inside. The advantage in this case is we don't try to expand array indexes like arr[i], or left-side array de-structuring cases like const [a, b].

The disadvantage is that we now don't show suggestions for abbreviations like div[a b]. Either the user must type an abbreviation of the form div[a=someValue b=someOtherValue], turn on emmet.triggerExpansionOnTab, or run the expand command. But, considering how often one means to type an array index or a left-side de-structuring, and how there already are workarounds, I think it is worth pushing in this mitigation to improve the QoL for JSX users.

I also improved some typing information so we use fewer anys.