Issue Type: Feature Request

This new feature is over-eager and triggers on unsaved files that are not part of the commit, which I don't think makes sense. If I have staged file A.js and am committing only file A.js, I should not receive a warning that B.js is unsaved. Ideally it will only consider staged files unless I am committing all staged and unstaged.

VS Code version: Code 1.30.2 (61122f8, 2019-01-07T22:54:13.295Z)
OS version: Windows_NT x64 10.0.17763