DOC: Clarify allowed values for on_bad_lines in read_csv (#58662)

* Clarify allowed values for on_bad_lines in read_csv Move the callable options out of the version added/changed tags and improve the flow. * typo space before colon * trim trailing whitespace

Author: wjandrea

pandas/io/parsers/readers.py

@@ -408,30 +408,32 @@ class _read_shared(TypedDict, Generic[HashableT], total=False):
  documentation for more details.
 on_bad_lines : {{'error', 'warn', 'skip'}} or Callable, default 'error'
  Specifies what to do upon encountering a bad line (a line with too many fields).
- Allowed values are :
+ Allowed values are:
 
  - ``'error'``, raise an Exception when a bad line is encountered.
  - ``'warn'``, raise a warning when a bad line is encountered and skip that line.
  - ``'skip'``, skip bad lines without raising or warning when they are encountered.
+ - Callable, function that will process a single bad line.
+ - With ``engine='python'``, function with signature
+ ``(bad_line: list[str]) -> list[str] | None``.
+ ``bad_line`` is a list of strings split by the ``sep``.
+ If the function returns ``None``, the bad line will be ignored.
+ If the function returns a new ``list`` of strings with more elements than
+ expected, a ``ParserWarning`` will be emitted while dropping extra elements.
+ - With ``engine='pyarrow'``, function with signature
+ as described in `pyarrow documentation
+ <https://arrow.apache.org/docs/python/generated/pyarrow.csv.ParseOptions.html
+ #pyarrow.csv.ParseOptions.invalid_row_handler>`_.
 
  .. versionadded:: 1.3.0
 
  .. versionadded:: 1.4.0
 
- - Callable, function with signature
- ``(bad_line: list[str]) -> list[str] | None`` that will process a single
- bad line. ``bad_line`` is a list of strings split by the ``sep``.
- If the function returns ``None``, the bad line will be ignored.
- If the function returns a new ``list`` of strings with more elements than
- expected, a ``ParserWarning`` will be emitted while dropping extra elements.
- Only supported when ``engine='python'``
+ Callable
 
  .. versionchanged:: 2.2.0
 
- - Callable, function with signature
- as described in `pyarrow documentation
- <https://arrow.apache.org/docs/python/generated/pyarrow.csv.ParseOptions.html
- #pyarrow.csv.ParseOptions.invalid_row_handler>`_ when ``engine='pyarrow'``
+ Callable for ``engine='pyarrow'``
 
 delim_whitespace : bool, default False
  Specifies whether or not whitespace (e.g. ``' '`` or ``'\\t'``) will be