Fix printing of comments before =>

[nicolo-ribaudo]

Q	A
Fixed Issues?	Fixes #15161
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

This fix conflicts with the fix proposed in #15159, however I believe that it solves the problem in a better way: we must keep the correct _noLineTerminator to make sure to disallow any multiline comment right before =>.

All these cases with multi-line comments before => cannot happen just by parsing+printing the source code, but can happen if plugins modify the AST. It's better to miss printing the comment (or to report an error, as in #15158), but we should never generate invalid code.

[babel-bot]

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[liuxingbaoyu]

This PR looks good to me, can we keep https://github.com/babel/babel/pull/15159/files#diff-6c32c344bfe1f4e77de24cdd3e427e84c4ac0a871380ff3720a7351cac63cb74R197-R198?
In my opinion this is better than being trailing Commens.

[nicolo-ribaudo]

Well, we could still keep the new this.printInnerComments(); call

[liuxingbaoyu]

The current this._noLineTerminator is automatically set to false, which I fear does not completely prevent all line breaks.

Also the output in #15161 is weird, it seems like we are wrapping comments for non-existent, it might be worth me to open a PR to optimize.

[nicolo-ribaudo]

The current this._noLineTerminator is automatically set to false, which I fear does not completely prevent all line breaks.

It's automatically set to false after printing a token/word. [no LineTerminator here] is only between two tokens, so after printing the second one is always safe to set _noLineTerminator to false.