DOC: Remove unnecessary `:func:` & `:meth:` parentheses

[mattwang44]

Pandas version checks

• I have checked that the issue still exists on the latest versions of the docs on main here

Location of the documentation

use regex pattern :(func|meth):`[^`]+()` to search for the occurrences

Documentation problem

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

.. bad
:func:`read_csv()`

.. good
:func:`read_csv`

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

Suggested fix for documentation

remove unnecessary :func: & :meth: parentheses in reST content