docs: clarify `clean: true` and default `include`

[agilgur5]

Summary

Minor docs clarifications, fixes, and style consistency

• Follow-up to #375

Details

• the docs for clean don't seem to have been updated after f15cb84dcc99a0bd20f3afce101c0991683010b6 (#68), which slightly changed how it works

• also clarify that "wipes out cache" means it deletes all previous caches by saying "wipes any existing cache" instead

• fix the include default explanation to mention .tsx files as well, since the regex includes those

  • also add code backticks and capitalize TypeScript etc (guess I missed this option in my previous docs PRs? or I intentionally left it as a separate change a while ago...)

• also add code backticks around node_modules in cacheRoot as well while at it

• use non-rendered newlines between sentences for markdown style consistency

[agilgur5]

Windows CI failures are due to #385 (we also don't have any docs tests at this time, so docs-only changes can't result in a CI failure anyway)