REF: refactor describe.py into the methods folder (#50559)

Author: kostyafarber

pandas/core/generic.py

@@ -142,7 +142,6 @@
 from pandas.core.arrays import ExtensionArray
 from pandas.core.base import PandasObject
 from pandas.core.construction import extract_array
-from pandas.core.describe import describe_ndframe
 from pandas.core.flags import Flags
 from pandas.core.indexes.api import (
     DatetimeIndex,
@@ -160,6 +159,7 @@
 )
 from pandas.core.internals.construction import mgr_to_mgr
 from pandas.core.internals.managers import _using_copy_on_write
+from pandas.core.methods.describe import describe_ndframe
 from pandas.core.missing import (
     clean_fill_method,
     clean_reindex_fill_method,