The point of the comment is that all 3 terms refer to the same thing. `git add` modifies staging area, `git diff --cached` shows the diff of things in the stage

The point of the comment is that all 3 terms refer to the same thing. `git add` modifies staging area, `git diff --cached` shows the diff of things in the staged area, and `git stash --keep-index` stashes things that haven't been staged (I think? IDK, I never use it). Maybe pick one?