Remove unnecessary `:func:` & `:meth:` parentheses from reST content

[mattwang44]

Describe the bug

The func & meth role's parentheses are unnecessary as Sphinx will add them to the rendered output.

.. bad
:func:`sphinx.locale._()`

.. good
:func:`sphinx.locale._`

We're introducing a new rule to the sphinx-lint (issue & PR) and, since sphinx-lint utilizes Sphinx doc content in the CI, we'd like to also fix the issue in doc.

[AA-Turner]

Could you do this for method roles too? See https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-add_function_parentheses

[mattwang44]

Could you do this for method roles too? See sphinx-doc.org/en/master/usage/configuration.html#confval-add_function_parentheses

Thanks, I've updated the PR and also the sphinx-lint PR!