doc: fix YAML documentation comment starts
This PR changes several YAML documentation comments starts from <!--YAML to <!-- YAML, to hopefully fix their content from being missing in the rendered documentation:
- https://nodejs.org/api/globals.html#globals_class_abortcontroller
- https://nodejs.org/api/packages.html#packages_subpath_imports
- https://nodejs.org/api/packages.html#packages_subpath_patterns
- https://nodejs.org/api/packages.html#packages_exports_sugar
- https://nodejs.org/api/packages.html#packages_conditional_exports
- https://nodejs.org/api/packages.html#packages_self_referencing_a_package_using_its_name
- https://nodejs.org/api/worker_threads.html#worker_threads_worker_setenvironmentdata_key_value
It would have saved me a lot of time over the past months had this information been rendering correctly, as I've been sifting through Node.js PRs, commits, and changelog entries, even at times doing local experiments with multiple Node.js versions
I'm not sure how to test the rendered docs locally (the contributing guide doesn’t mention how to?) to be sure the missing spaces at the start of the YAML comments is the problem, but it seems to be the only difference between what does or doesn’t display.