DOC: Surprising behavior on DataFrame.squeeze() with 0 or 1 col/row
``` python
pd.DataFrame({"A": [1]}).squeeze()  # -> 1
pd.DataFrame({"A": []}).squeeze()  # Noop
```

The second one is genuinely surprising; I would have expected it to return an empty Series with the name set to `A`. But it is consisent with numpy (`np.array([[], []]).squeeze()`) so I've marked is as a doc issue.
