[Metadata Composite Keys] Update set_primary_key docstring

[pvk-developer]

Resolves #2824
CU-86b8n8h1r

[sdv-team]

Task linked: CU-86b8n8h1r SDV - [Metadata composite keys] Update set_primary_key docstring to indicate a list of columns is now valid #2824

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.06%. Comparing base (d7b8b4c) to head (61337c0).
⚠️ Report is 1 commits behind head on feature/metadata-composite-keys.

Additional details and impacted files

@@                       Coverage Diff                        @@
##           feature/metadata-composite-keys    #2841   +/-   ##
================================================================
  Coverage                            98.06%   98.06%           
================================================================
  Files                                   73       73           
  Lines                                 8278     8278           
================================================================
  Hits                                  8118     8118           
  Misses                                 160      160           

Flag	Coverage Δ
integration	75.62% <ø> (ø)
unit	97.08% <ø> (ø)

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[fealho]

The issue also asks to "update the docstring for SingleTableMetadata.set_primary_key".

[sdv-team]

This Pull Request is not linked to an issue. To ensure our community is able to accurately track resolved issues, please link any issue that will be closed by this PR!

[sdv-team]

This Pull Request is not linked to an issue. To ensure our community is able to accurately track resolved issues, please link any issue that will be closed by this PR!

[sdv-team]

This Pull Request is not linked to an issue. To ensure our community is able to accurately track resolved issues, please link any issue that will be closed by this PR!