[ENH] polars complete function

[samukweku]

PR Description

Please describe the changes proposed in the pull request:

• Add complete method for polars

This PR relates to #1352 .

PR Checklist

Please ensure that you have done the following:

1. PR in from a fork off your branch. Do not PR from <your_username>:dev, but rather from <your_username>:<feature-branch_name>.

2. If you're not on the contributors list, add yourself to AUTHORS.md.

3. Add a line to CHANGELOG.md under the latest version header (i.e. the one that is "on deck") describing the contribution.
   • Do use some discretion here; if there are multiple PRs that are related, keep them in a single line.

Automatic checks

There will be automatic checks run on the PR. These include:

• Building a preview of the docs on Netlify
• Automatically linting the code
• Making sure the code is documented
• Making sure that all tests are passed
• Making sure that code coverage doesn't go down.

Relevant Reviewers

Please tag maintainers to review.

• @ericmjl

[codecov]

Codecov Report

Attention: Patch coverage is 96.05263% with 3 lines in your changes missing coverage. Please review.

Project coverage is 85.93%. Comparing base (62c57c6) to head (af09c7a).
Report is 19 commits behind head on dev.

❗ Current head af09c7a differs from pull request most recent head 0f24a6e

Please upload reports for the commit 0f24a6e to get more accurate results.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev    #1367      +/-   ##
==========================================
- Coverage   94.48%   85.93%   -8.55%     
==========================================
  Files          80       83       +3     
  Lines        4367     4820     +453     
==========================================
+ Hits         4126     4142      +16     
- Misses        241      678     +437     

[ericmjl]

Wonderful, thank you @samukweku!