[release/4.0] Fix up docs for MLContext

[github-actions]

Backport of #7334 to release/4.0

/cc @michaelgsharp @gewarren

Customer Impact

Testing

Risk

[michaelgsharp]

Merging before checks are done since its just a docs change, but its xml code docs so it triggered all the builds.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.89%. Comparing base (763cbb7) to head (c436a5a).
Report is 4 commits behind head on release/4.0.

Additional details and impacted files

@@               Coverage Diff               @@
##           release/4.0    #7363      +/-   ##
===============================================
- Coverage        68.90%   68.89%   -0.01%     
===============================================
  Files             1470     1470              
  Lines           274079   274079              
  Branches         28405    28405              
===============================================
- Hits            188841   188830      -11     
- Misses           77922    77931       +9     
- Partials          7316     7318       +2     

Flag	Coverage Δ
Debug	68.89% <ø> (-0.01%)	⬇️
production	63.30% <ø> (-0.01%)	⬇️
test	89.42% <ø> (+<0.01%)	⬆️

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Files with missing lines	Coverage Δ
src/Microsoft.ML.AutoML/API/ColumnInference.cs	100.00% <ø> (ø)
...ML.AutoML/ColumnInference/ColumnInformationUtil.cs	84.54% <ø> (ø)
src/Microsoft.ML.Data/MLContext.cs	85.71% <ø> (ø)
...ML.TorchSharp/NasBert/SentenceSimilarityTrainer.cs	89.39% <ø> (ø)
...ML.TorchSharp/NasBert/TextClassificationTrainer.cs	95.65% <ø> (ø)

... and 8 files with indirect coverage changes