Fix multibyte character handling

[natemoo-re]

Changes

• Closes Compilation error occurs when using Japanese in .astro component. astro#9421
• Closes 🐛 BUG: Styling an emoji - runtime error: index out of range [11] with length 11 #733
• When generating sourcemaps, we were unconditionally accessing an index. For multi-byte characters, this index was sometimes out of range.
• This PR adds a len() check before access the index, which guards against the issue.
• There might be a more fundamental fix here, but I really don't think it's a great idea to dig into the sourcemapping logic to try to find it.

Testing

Tests added for cases that have been reported to throw

Docs

Bug fix only

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🦋 Changeset detected

Latest commit: acf9fe9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@astrojs/compiler	Patch

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[Princesseuh]

Can be tackled separately just to fix the crash, however it'd be great to have a sourcemap test with multi bytes characters to make sure this didn't break stuff!

[natemoo-re]

@Princesseuh Added some sourcemap-specific tests in 525b6cc! Everything seems to be working well.

[Princesseuh]

@Princesseuh Added some sourcemap-specific tests in 525b6cc! Everything seems to be working well.

Testing JS sourcemaps with the annotations would be great since the bug started there! But it's great that it works for TSX

[MoustaphaDev]

LGTM!