Improve bashit upgrade function git log and add missing popd

[tbhaxor]

Description

Having merge logs with actual changes was too noisy. So in this PR, it will be removed and actual commits will be shown. Also when the upgrade fails, the directory doesn't change back to the source directory, rather it stayed in $BASH_IT directory. So I have also added popd just before returning the function.

Motivation and Context

How Has This Been Tested?

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)

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.

[NoahGorny]

I like it, thank you @tbhaxor !