Add sdkman bash completion to the list of clean files

[marcospereira]

Description

Add sdkman bash completion to the list of clean files, fix the issues reported by shellcheck, and reformat the code with shfmt.

Motivation and Context

Follow up to #1763 as suggested by @NoahGorny.

How Has This Been Tested?

Manually, the same way #1763 was tested before. See bash version there.

Screenshots (if appropriate):

Types of changes

• 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)
• Code clean up

Checklist:

• My code follows the code style of this project.
• If my change requires a change to the documentation, I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• 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.

[davidpfarrell]

Using "Hide whitespace changes" to review the diffs, and everything looks like I would expect.

Thanks!

[NoahGorny]

Great job @marcospereira!