DEP: Break numpydoc.cli dependence on sphinx.

The only thing here that depends on sphinx is the
fn which uses docscrape_sphinx's version of get_doc_object.
If we switch to docscrape's version of get_doc_object, then the
resulting rendering is derived from NumpyDocString instead of
SphinxDocString.

Alternatively - this could be left as-is and the test_render tests
in  could be importorskipped.

Author: rossbar

numpydoc/cli.py

@@ -6,7 +6,7 @@
 from pathlib import Path
 from typing import List
 
-from .docscrape_sphinx import get_doc_object
+from numpydoc.docscrape import get_doc_object
 from .hooks import utils, validate_docstrings
 from .validate import ERROR_MSGS, Validator, validate
 

numpydoc/docscrape.py

@@ -574,7 +574,7 @@ def dedent_lines(lines):
 
 
 class FunctionDoc(NumpyDocString):
-    def __init__(self, func, role="func", doc=None, config=None):
+    def __init__(self, func, role=None, doc=None, config=None):
         self._f = func
         self._role = role  # e.g. "func" or "meth"