Fallback to an option when transients fail

[arunshenoy99]

Proposed changes

Type of Change

• Bugfix (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 not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• Linting and tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

1. This replicates (in the right place): Option fallback bluehost/wp-sso-mu-plugin#2.
2. It also adds support for linting and formatting PHP files.

[wpscholar]

Thanks @arunshenoy99! We'll be working on getting this fix rolled out today in an out-of-cycle Bluehost plugin release.