Add overload for ColumnCollection.get(col, default)

[mark-thm]

Description

Fixes #11328 by adding an overload to ColumnCollection when a non-None default is provided.

Checklist

This pull request is:

• [ ] A documentation / typographical / small typing error fix
  • Good to go, no issue or tests are needed
• [x] A short code fix
  • please include the issue number, and create an issue if none exists, which must include a complete example of the issue. one line code fixes without an issue and demonstration will not be accepted.
  • Please include: Fixes: #<issue number> in the commit message
  • please include tests. one line code fixes without tests will not be accepted.
• [ ] A new feature implementation
  • please include the issue number, and create an issue if none exists, which must include a complete example of how the feature would look.
  • Please include: Fixes: #<issue number> in the commit message
  • please include tests.

[sqla-tester]

New Gerrit review created for change dca7c80f0af0a0bcacc76f4d35b39aea29ba8050: https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/5286

[sqla-tester]

Patchset 32db849e0df1db357df79df3a0dc2263a755d04e added to existing Gerrit review https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/5286

[sqla-tester]

Gerrit review https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/5286 has been merged. Congratulations! :)

[sqla-tester]

Gerrit review https://gerrit.sqlalchemy.org/c/sqlalchemy/sqlalchemy/+/5289 has been merged. Congratulations! :)