swift: palindromic-number

Congrats on taking the first step to contributing to the Sample Programs repository maintained by The Renegade Coder! For simplicity, please make sure that your pull request includes one and only one contribution.

Please fill one of the sections below as applicable. Please also add any other relevant information to the Notes section at the bottom. You may delete or just ignore any other sections. For more information please refer to our contributing documentation

## I Am Adding a New Code Snippet in an Existing Language

[x] I fixed #4033
[x] I named the pull request using Add {palindromic-number} in {swift} format

I Am Adding a New Code Snippet in a New Language

[ ] I fixed #your-issue-number-here
[ ] I named the pull request using Add {PROJECT} in {LANGUAGE} format
[ ] I added a testinfo.yml files (see contributing documentation)
- [ ] I used an officially supported docker image or one that I personally trust

I Am Adding New Tests for a Project

[ ] I fixed #your-issue-number-here
[ ] I named the pull request using Add {PROJECT} Tests format
[ ] I verified the project exists on the Sample Programs Project List
[ ] I added tests for every test case in the Testing table of the project description for the given project. (See contributing documentation)

I Am Adding New Tests for a Language

[ ] I fixed #your-issue-number-here
[ ] I named the pull request using Add {LANGUAGE} Tests format
[ ] I added a testinfo.yml files (see contributing documentation)
- [ ] I used an officially supported docker image or one that I personally trust
[ ] I verified all tests are passing

I Am Modifying an Existing Code Snippet or Existing Tests

[ ] I fixed #your-issue-number-here
[ ] I have read about modifying existing code snippets or tests in the contributing documentation
[ ] I have explained why this modification is necessary either in the issue linked above or in the notes below
[ ] I named the pull request using Modify {PROJECT} {tests} in {LANGUAGE} format

Other Notes

Add notes here...

TheRenegadeCoder / sample-programs