chore: improve lint:docs script

[iuioiua]

Now, assertions use assert() instead of manually pushing to diagnostics.

Step towards having this be a tool that other codebases can use.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.74%. Comparing base (f8894da) to head (cf0988b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6625   +/-   ##
=======================================
  Coverage   94.74%   94.74%           
=======================================
  Files         583      583           
  Lines       46478    46478           
  Branches     6523     6523           
=======================================
+ Hits        44036    44037    +1     
+ Misses       2399     2398    -1     
  Partials       43       43           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[kt3k]

Other part looks good to me

[kt3k]

LGTM