feat: make deletion line highlight wider

[Patrick-Erichsen]

Description

This is the main fix: https://github.com/continuedev/continue/compare/nate/jetbrains-inline-diff-red...pe/jb-highlights?expand=1#diff-17cb756c324178a0fc001dd39fd6d58f172f6180a0f19a8c89c0fbbfbe0d045cR93

Checklist

• [ ] The base branch of this PR is dev, rather than main
• [ ] The relevant docs, if any, have been updated or created

Screenshots

Testing

[ For new or modified features, provide step-by-step testing instructions to validate the intended behavior of the change. ]