Git Diff Context Provider Hash Awareness

[rootedbox]

Validations

• [X] I believe this is a way to improve. I'll try to join the Continue Discord for questions
• [X] I'm not able to find an open issue that requests the same enhancement

Problem

Allow Passing of hashes or head~X to the git diff so I can ask questions about changes between historical changes.

Solution

Switch DiffContextProvider to be of type "submenu".. might possibly need custom dialog.