Before:
{
  "staged": [
    "notes.txt",
    "other.txt"
  ],
  "unstaged": [],
  "notes": "version two"
}
After git restore --staged -- notes.txt:
{
  "staged": [
    "other.txt"
  ],
  "unstaged": [
    "notes.txt"
  ],
  "notes": "version two"
}
HEAD unchanged: True
Temporary demo removed.
