Fix docs path in snippet test and exclude subdirs

[ToastCheng]

1. Fix docs path in snippet test and exclude md under hardware and google
2. Fix exec error in md files

Partially implements #7787

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.57%. Comparing base (a764b67) to head (6c17e8a).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7798   +/-   ##
=======================================
  Coverage   99.57%   99.57%           
=======================================
  Files        1102     1102           
  Lines       98434    98529   +95     
=======================================
+ Hits        98014    98109   +95     
  Misses        420      420           

☔ 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.

[pavoljuhas]

LGTM after pushing a few tweaks, mainly to avoid creating scratch test file from testing of serialization.md.