Git operations are not updating the document manager

[charlespwd]

Describe the bug
Git operations change files in the workspace without shooting textDocument/did{Open,Change,Save,Close} lifecycle notifications.

This means that if you revert changes and do a rename, then the internal representation of preloaded files might be off.

Expected behaviour
When files are modified "under our feet", we need to sync them to the document manager with updated values

Actual behaviour
Stale values are kept around