Deprecate prefix argument in read_csv and read_table

[phofl]

• closes DEPR: prefix argument in read_csv/read_table #43396
• tests added / passed
• Ensure all linting tests pass, see here for how to run them
• whatsnew entry

cc @lithomas1 I am also on board with deprecating this. I don't think the keyword adds real value

[asishm]

shouldn't this be prefix (and not header)?

[phofl]

thx

[lithomas1]

Using parser.read_csv_check_warnings should fix the stacklevel issues.

pandas/pandas/tests/io/parser/conftest.py

Lines 31 to 39 in bdff214

	def read_csv_check_warnings(
	self, warn_type: type[Warning], warn_msg: str, *args, **kwargs
	):
	# We need to check the stacklevel here instead of in the tests
	# since this is where read_csv is called and where the warning
	# should point to.
	kwargs = self.update_kwargs(kwargs)
	with tm.assert_produces_warning(warn_type, match=warn_msg):
	return read_csv(*args, **kwargs)

It would be also nice to add an example to the user guide of how to add a prefix to the names.

[jreback]

thanks @phofl