Fix #11275: _get_doc_blocks is crashing parsing if .format is called

[aranke]

Resolves #11275

Problem

_get_doc_blocks was crashing if we used .format on a string or doc block.

Solution

Add an additional check in _get_doc_blocks and a couple tests.

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.91%. Comparing base (7041e58) to head (ed0d75e).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #11310      +/-   ##
==========================================
- Coverage   88.95%   88.91%   -0.05%     
==========================================
  Files         189      189              
  Lines       24169    24170       +1     
==========================================
- Hits        21500    21490      -10     
- Misses       2669     2680      +11     

Flag	Coverage Δ
integration	86.17% <ø> (-0.11%)	⬇️
unit	62.53% <ø> (+<0.01%)	⬆️

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Components	Coverage Δ
Unit Tests	62.53% <ø> (+<0.01%)	⬆️
Integration Tests	86.17% <ø> (-0.11%)	⬇️