Make remaining MR filters use sentence case

What does this MR do and why?

Make the MR filters use sentence case:

• Approved-By to Approved by
• Merged-By to Merged by
• Deployed-after to Deployed after
• Deployed-before to Deployed before

References

UI text: filters should have consistent spelling (#526006 - closed)

Screenshots or screen recordings

Description	Before	After
Search MRs (dropdown)
Search MRs (tokens):

How to set up and validate locally

In GDK, check the following locations:

• Group MRs: http://gdk.test:3000/groups/gnuwget/-/merge_requests
• Project MRs: http://gdk.test:3000/gnuwget/Wget2/-/merge_requests

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.