[DOP-23982] Use tabs for complex code examples

[dolfinus]

Change Summary

Before:
https://onetl.readthedocs.io/en/latest/

After:
https://onetl--344.org.readthedocs.build/en/344/

Most of changes is just additional indentation in docstrings.

Related issue number

Checklist

• Commit message and PR title is comprehensive
• Keep the change as small as possible
• Unit and integration tests for the changes exist
• Tests pass on CI and coverage does not decrease
• Documentation reflects the changes where applicable
• docs/changelog/next_release/<pull request or issue id>.<change type>.rst file added describing change
  (see CONTRIBUTING.rst for details.)
• My PR is ready to review.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.47%. Comparing base (35cd86e) to head (0aa55c7).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #344      +/-   ##
===========================================
- Coverage    92.48%   92.47%   -0.02%     
===========================================
  Files          228      228              
  Lines         9875     9875              
  Branches      1013     1013              
===========================================
- Hits          9133     9132       -1     
  Misses         556      556              
- Partials       186      187       +1     

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