feat: exclude lines that are missing from source maps

[AriPerkkio]

• Closes Comments are reported as not covered #238
• Supersedes and closes feat: exclude lines from processing #212
• Supersedes and closes Ignore lines from code coverage which are not executable #242

feat: exclude lines that are missing from source maps

• When source maps are available, use @jridgewell/trace-mapping to figure out which lines contain runtime code. If a line is not present in source maps, consider it as empty line. This will exclude Typescript typings, comments, empty lines and any other special syntax that transpiled languages exclude from source maps.
• Should this be considered as breaking change or be a configurable option? ⚠️
  • This is now opt-in and configurable via excludeEmptyLines argument. No breaking changes.

Examples:

• Vitest

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• Jest

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• Playwright

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• c8, test code transpiled with tsc. It seems to leave comments in source maps - esbuild doesn't.

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fix: ignore hint to exclude lines

• /* v8 ignore ... */ should exclude the lines from coverage, not mark them as covered.
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[AriPerkkio]

Any thoughts about this approach @SimenB and @bcoe?

In Vitest we will always have source maps available so we can utilize those for analysing the source file. I believe Jest has them too? I'm not that sure about c8 though.

When source maps are not passed, the empty lines should be marked as covered as before.