Highlight differences within lines of suggestions in merge requests

Problem to solve

The Suggested change diff only indicates that a difference exists on a line, but not the specific text within the line that differs, so it can be difficult to scan the content to identify the actual change.

For example, the diff from this MR being commented on does show a darker highlight, indicating the specific changes within the changed lines. The suggestion below it does not.

Intended users

All who perform code review, but may be especially helpful to those editing and reviewing text.

Further details

TBD

Proposal

TBD

Permissions and Security

Documentation

Confirm that no screenshots exist of Suggestions that don't display this new highlighting. Otherwise, no further clarity is likely needed in docs, unless we want to add coverage about this type of darker highlighting. I am not sure if we have a term for it.

Testing

What does success look like, and how can we measure that?

Links / references