depr(python): Deprecate arctan2d in favor of arctan2(...).degrees()

[stinodego]

Changes

• Deprecate arctan2d. Users should use pl.arctan2(...).degrees() instead.

Example

Before

>>> lf = pl.LazyFrame({"a": [0, 1], "b": [-1, 0]})
>>> lf.select(pl.arctan2d("a", "b")).collect()
shape: (2, 1)
┌───────┐
│ a     │
│ ---   │
│ f64   │
╞═══════╡
│ 180.0 │
│ 90.0  │
└───────┘

After

>>> lf.select(pl.arctan2("a", "b").degrees()).collect()
shape: (2, 1)
┌───────┐
│ a     │
│ ---   │
│ f64   │
╞═══════╡
│ 180.0 │
│ 90.0  │
└───────┘