Fix linter errors for web-worker.md

Editor assessment

For a lint-only cleanup, this is appropriately minimal: `docs: fix linter errors for web-worker.md` identifies the exact file, uses imperative mood, and needs no further explanation. No scope is used, which is fine for docs-wide changes but slightly reduces filterability. The body contains only the `PR Close` trailer, acceptable because the subject fully states the what, and a why is rarely needed for formatting fixes. One might quibble that "fix linter errors" without a scope is almost `style` territory, but for documentation files `docs` is the conventional choice. Compliant and clear.