API/DEPR: error_bad_lines/warn_bad_lines in pd.read_csv

[h-vetinari]

From discussion started in #22639:

Currently, pd.read_csv has two booleans

• error_bad_lines : boolean, default True
  Lines with too many fields (e.g. a csv line with too many commas) will by default cause an exception to be raised, and no DataFrame will be returned. If False, then these “bad lines” will dropped from the DataFrame that is returned.
• warn_bad_lines : boolean, default True
  If error_bad_lines is False, and warn_bad_lines is True, a warning for each “bad line” will be output.

This is confusing (what happens if both are True), and not in line with other errors-kwargs that are all around the place. Clearer would be something like: error_bad_lines = {'raise'|'warn'|'ignore'}, and removing warn_bad_lines.

[gfyoung]

This is a pretty reasonable suggestion and is consistent with what we do with other functions from an API standpoint (e.g. to_numeric).

[lithomas1]

closing as duplicate of #15122