feat: decorate MR files

@X_Sheep Thank you for implementing this change (twice), I only shuffled the code around a bit. Credit goes to @X_Sheep.

Description

This MR adds changeType to the MR diff URIs. This will allow us to show decoration (text color in the tab label) based on the change type.

before	after

Related Issues

MR from @X_Sheep !1416 (closed)

The file decoration provider for Merge Requests was added in !1355 (merged) and subsequently removed in !1387 (merged), because the changes in URLs caused other features to become unreliable.

How has this been tested?

Opening changed files in MR review panel and seeing that the decoration color matches the change type.

Also, make sure that changed files with comments still show them

Example MR: viktomas/test-project!11

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)
• Documentation
• Chore (Related to CI or Packaging to platforms)
• Test gap