Add Transform iter to itx

[BooleanCat]

Transform is a limited form of Map where the argument type is the same as the return type, allowing it to be chained.

Add Transform iter to itx.

Transform is a limited form of Map where the argument type is the same as the return type, allowing it to be chained.

Which issue does this change relate to?

N/A.

Contribution checklist.

• [x] I have read and understood the CONTRIBUTING guidelines
• [x] All commits in my PR conform to the commit hygiene section
• [x] I have added relevant tests
• [x] I have not added any dependencies

Additional context

N/A.

[codecov[bot]]

Codecov Report

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

Project coverage is 100.00%. Comparing base (56afa4a) to head (55a9f6c).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #129 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 31 32 +1 Lines 378 382 +4 ========================================= + Hits 378 382 +4 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.