Improve override examples

[flack]

See discussion in #5439

I'm pretty sure that the typical use case for folder-level overrides is to exclude an entire subtree, not just the files directly in this folder (I mean, who would have a documentation or vendor folder and then inside of it a subfolder with regular code?). So I've changed the examples to cover this typical use case by default

Description

Checklist:

• I am associating a language with a new file extension.

  • The new extension is used in hundreds of repositories on GitHub.com
    • Search results for each extension:
      • https://github.com/search?utf8=%E2%9C%93&type=Code&ref=searchresults&q=extension%3AFOOBAR+KEYWORDS+NOT+nothack
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a change to the heuristics to distinguish my language from others using the same extension.

• I am adding a new language.

  • The extension of the new language is used in hundreds of repositories on GitHub.com.
    • Search results for each extension:
      • https://github.com/search?utf8=%E2%9C%93&type=Code&ref=searchresults&q=extension%3AFOOBAR+KEYWORDS+NOT+nothack
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a syntax highlighting grammar: https://github-lightshow.herokuapp.com/
  • I have updated the heuristics to distinguish my language from others using the same extension.

• I am fixing a misclassified language

  • I have included a new sample for the misclassified language:
    • Sample source(s):
      • [URL to each sample source, if applicable]
    • Sample license(s):
  • I have included a change to the heuristics to distinguish my language from others using the same extension.

• I am changing the source of a syntax highlighting grammar

  • Old: https://github-lightshow.herokuapp.com/
  • New: https://github-lightshow.herokuapp.com/

• I am updating a grammar submodule

• I am adding new or changing current functionality

  • I have added or updated the tests for the new or changed functionality.

• I am changing the color associated with a language

  • I have obtained agreement from the wider language community on this color change.
    • [URL to public discussion]
    • [Optional: URL to official branding guidelines for the language]

[lildude]

Copying from #5316 (comment)

As with previous attempts to make this change in #4992 and #4889, you're making assumptions about the developer's intentions and resorting to using the sledgehammer approach. The developer may have intended to only apply to the files in that directory and not recursing. See #4889 (comment) for another discussion on this.

Ultimately, this is really about understanding the git documentation and the developer's end goals, and not making any assumptions, which are outside the scope of using Linguist.

[flack]

@lildude sure, more examples can never hurt. do you want me to update this PR or are you going to commit this separately? If I should make the change: Should I add a second commit or just force-push?

[lildude]

You should be able to merge my suggestions from the UI. Don’t worry about the history as we squash all commits when merging.

[flack]

@lildude done

[lildude]

Thanks for taking on my suggestions. I think this will help reduce this kind of confusion without making assumptions and encouraging peeps to blindly swing the old sledgehammer 😄.

[lildude]

Test failures aren't related and this is only a doc change so I'm gonna merge.