Fix typos in documentation

[larrybradley]

The second commit also replaces tabs with spaces in using_datamodels.rst.

Checklist

• Added entry in CHANGES.rst under the corresponding subsection
• updated relevant tests
• updated relevant documentation
• Passed romancal regression testing on Jenkins / PLWishMaster. Link: https://plwishmaster.stsci.edu:8081/job/RT/job/romancal/XXX/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.27%. Comparing base (087a60d) to head (95182b4).
Report is 15 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #340      +/-   ##
==========================================
- Coverage   97.56%   97.27%   -0.29%     
==========================================
  Files          30       31       +1     
  Lines        2788     3048     +260     
==========================================
+ Hits         2720     2965     +245     
- Misses         68       83      +15     

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[PaulHuwe]

LGTM

[larrybradley]

I don't have repo permissions to label or merge this PR.

[larrybradley]

The pre-commit codespell test failed due to a typo in the changelog, so I just fixed that one too. 😄

[PaulHuwe]

Let me know when you are ready for this to be merged.

[larrybradley]

Merge away!