Search api 1 cleanup

[SpacemanPaul]

Reason for this pull request

Take advantage of Python 3.10 type hint enhancements, and fix incorrect typehints.

• [x] Tests added / passed
• [x] Fully documented, including docs/about/whats_new.rst for all changes

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (9585230) 85.43% compared to head (c44991b) 85.43%.

:exclamation: Current head c44991b differs from pull request most recent head 7a8a29a. Consider uploading reports for the commit 7a8a29a to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop-1.9 #1541 +/- ## ============================================ Coverage 85.43% 85.43% ============================================ Files 140 140 Lines 15044 15047 +3 ============================================ + Hits 12853 12856 +3 Misses 2191 2191 ```

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