API: rename PandasArray -> NumpyExtensionArray

[jbrockmendel]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

NA

Issue Description

More neutral naming scheme analogous to ArrowExtensionArray.

Expected Behavior

NA

Installed Versions

Replace this line with the output of pd.show_versions()

[SanjithChockan]

take

[jbrockmendel]

@TomAugspurger i think PandasArray was your idea initially. any objection to renaming?

[TomAugspurger]

Works for me.