Merge pull request scipy#14844 from AnirudhDagar/doc_refguide

DOC: Add refguide_check option details to runtests.rst

doc/source/dev/contributor/runtests.rst

@@ -87,6 +87,9 @@ Other useful options include:
    docs are built only in the ``html-scipyorg`` format, but you can
    change this by appending the name of the desired format
    (e.g. ``--doc latex``).
+- ``--refguide-check`` to check whether the objects in a Scipy submodule's
+    ``__all__`` dict correspond to the objects included in the reference
+    guide. It also checks the validity of code samples in docstrings.
 - ``--bench`` to run all benchmarks. See :ref:`benchmarking-with-asv`.
 - ``--pep8`` to perform pep8 check.
 - ``--mypy`` to run *mypy* on the codebase.