Clean `elixr.theme.bash`

[hyperupcall]

Description

Followed instructions in #1696 to cleanup elixr.theme.bash

Motivation and Context

Addresses #1696

How Has This Been Tested?

Ran ./lint_clean_files.sh

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [x] Clean

Checklist:

• [x] My code follows the code style of this project.
• [x] If my change requires a change to the documentation, I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] If I have added a new file, I also added it to clean_files.txt and formatted it using lint_clean_files.sh.
• [ ] I have added tests to cover my changes, and all the new and existing tests pass.

[hyperupcall]

It seems that this is the reason why macOS 12 tets consistently fail.