TweakReg: doc updates.

[mairanteodoro]

Resolves RCAL-527

This PR addresses updates to the RomanCal version of TweakReg.

Checklist

• added entry in CHANGES.rst under the corresponding subsection
• updated relevant tests
• updated relevant documentation
• updated relevant milestone(s)
• added relevant label(s)

[codecov]

Codecov Report

Patch coverage: 92.85% and project coverage change: +0.81 🎉

Comparison is base (b7ceecd) 63.74% compared to head (6d92ea5) 64.56%.

❗ Current head 6d92ea5 differs from pull request most recent head c0c25dd. Consider uploading reports for the commit c0c25dd to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #673      +/-   ##
==========================================
+ Coverage   63.74%   64.56%   +0.81%     
==========================================
  Files          78       78              
  Lines        4115     4117       +2     
==========================================
+ Hits         2623     2658      +35     
+ Misses       1492     1459      -33     

Flag	Coverage Δ		*Carryforward flag
nightly	63.64% <ø> (+0.12%)	⬆️	Carriedforward from 587c482

*This pull request uses carry forward flags. Click here to find out more.

Impacted Files	Coverage Δ
romancal/tweakreg/tweakreg_step.py	62.92% <92.30%> (+12.54%)	⬆️
romancal/tweakreg/astrometric_utils.py	92.42% <100.00%> (+0.11%)	⬆️

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[schlafly]

Looks good. Two minor questions about tweakreg features that make sense at L3 time but which I don't really understand at L2 time. One other thing that would be nice would be an example invocation of the pipeline with a custom catalog. There's a lot of code documentation there but not very much user-facing documentation there.

[schlafly]

These docs still look good to me. I am a bit confused, though---mostly in my last review I wanted some clarification about what a couple things did when tweakreg is used at L2 time, which is the default case for Roman. There we don't have overlaps and some steps presumably get skipped. I think we should make this default case very clear.

I also thought that some user facing documentation of the custom catalog option would be valuable, since a lot of the docs talked about the API but as a user I would have liked to see e.g. an invocation that used that feature. I don't think that additional documentation is strictly necessary if it's hard or if we don't have a CLI to that bit of the step, though.

[mairanteodoro]

These docs still look good to me. I am a bit confused, though---mostly in my last review I wanted some clarification about what a couple things did when tweakreg is used at L2 time, which is the default case for Roman. There we don't have overlaps and some steps presumably get skipped. I think we should make this default case very clear.

I also thought that some user facing documentation of the custom catalog option would be valuable, since a lot of the docs talked about the API but as a user I would have liked to see e.g. an invocation that used that feature. I don't think that additional documentation is strictly necessary if it's hard or if we don't have a CLI to that bit of the step, though.

We added an "Examples" page to the TweakReg docs with three scenarios, including the case where the user provides the source catalog instead of using the one provided by SourceDetection.