DOC: Slightly broken grammar for `groupby.apply` with fix (good first doc issue?)

[ianozsvald]

Location of the documentation

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.core.window.rolling.Rolling.apply.html

Documentation problem

For engine we have None : Defaults to 'cython' or globally setting compute.use_numba

Suggested fix for documentation

I'm very confident that this should read None : Defaults to 'cython' or the global setting in compute.use_numba.

Following the source code for apply to https://github.com/pandas-dev/pandas/blob/v1.2.3/pandas/core/window/rolling.py#L1307 and https://github.com/pandas-dev/pandas/blob/v1.2.3/pandas/core/util/numba_.py#L17 neither place sets the global variable, they just read from it.

[mroeschke]

Sure, your suggested edit is clearer. PRs welcome!

[Mayurji]

Shall I make the changes ? This would be my first contribution.

[MarcoGorelli]

sure go ahead