fix: drop keyword-end source map mapping

[ajhoddinott]

The trailing mapping at column + keyword.length introduced in #116 lands on whitespace, causing downstream source-map consumers to resolve adjacent expression positions onto whitespace columns.

For example with single-line return <logical-expression> lines in Svelte 5 .svelte.js rune modules, istanbul branchMap entries from @vitest/coverage-v8 via ast-v8-to-istanbul drift one column left into the keyword's trailing whitespace, and are reported as spurious uncovered branches.

I think the keyword-start mapping in #116 is sufficient for the debugger / stack-frame use cases it targets, so dropping the end mapping is the minimal fix.

[changeset-bot]

🦋 Changeset detected

Latest commit: 02b115e

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

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esrap	Patch

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[Rich-Harris]

Thanks — have to admit I'm a bit surprised at this finding, I would have thought that more mappings would always make things more accurate, never less (as long as they're correct of course). What's the simplest way to reproduce this?

[manuel3108]

Also seems like your local setup has a different formatting setup, could you please reduce the diff as much as possible?

[ajhoddinott]

What's the simplest way to reproduce this?

I've made a reduced case here:
https://github.com/ajhoddinott/esrap-coverage-reproduction

pnpm test

-----------------|---------|----------|---------|---------|-------------------
File             | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-----------------|---------|----------|---------|---------|-------------------
All files        |    87.5 |      100 |     100 |     100 |
 state.svelte.js |    87.5 |      100 |     100 |     100 |
-----------------|---------|----------|---------|---------|-------------------

Add to pnpm-workspace.yaml

overrides:
  esrap: 2.2.6

to downgrade then pnpm test again

-----------------|---------|----------|---------|---------|-------------------
File             | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-----------------|---------|----------|---------|---------|-------------------
All files        |     100 |      100 |     100 |     100 |
 state.svelte.js |     100 |      100 |     100 |     100 |
-----------------|---------|----------|---------|---------|-------------------