Methods section is now recognized in NumPy-style docstrings

Previously, the Methods section in a NumPy-style docstring was not recognized

New behavior:

    class Parent(metaclass=DocInheritMeta(style="numpy_with_merge"))::
        """Parent summary.

        Methods
        -------
        meth
        """
        pass

    class Child(Parent):
        """Child summary.

        Attributes
        ----------
        a: hello
        """
        pass

Child will have the docstring

Child summary.

Attributes
----------
a: hello

Methods
-------
 meth