Add support for poetry.lock

[smola]

Description

• Mark poetry.lock as TOML and generated. Fixed About poetry.lock #4882
• Added sample from poetry project (MIT license):
  https://github.com/python-poetry/poetry/blob/b19873ae4f4391b89bd6fe89aed52963c44db078/poetry.lock

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?q=filename%3Apoetry.lock+package+NOT+nothack&type=Code
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s): https://github.com/python-poetry/poetry/blob/b19873ae4f4391b89bd6fe89aed52963c44db078/poetry.lock
    • Sample license(s): MIT
  • I have included a change to the heuristics to distinguish my language from others using the same extension. (N/A)

[pchaigno]

Could you also add that new filename to the TOML entry in languages.yml?

[smola]

@pchaigno Unless I'm missing something, it's already there:
https://github.com/github/linguist/pull/4920/files#diff-3552b1a64ad2071983c4d91349075c75R5383

[pchaigno]

@pchaigno Unless I'm missing something, it's already there:
https://github.com/github/linguist/pull/4920/files#diff-3552b1a64ad2071983c4d91349075c75R5383

🤦 Not sure how I missed that.