Support comments as part of multiline values in configparser

Feature or enhancement

Proposal:

Today's configparser module does not consider lines being properly indented and starting with a comment_prefixes to be part of a multiline value. This can lead to unintended data loss during reading an INI file as:
config.ini

# I am a comment
    # I am also a comment
[dummy]
# I am a comment
key = I am a multiline
# I am a comment
    # multiline part which is not considered but should be
    being again part
# I am a comment

test.py

import configparser
config = configparser.ConfigParser(comment_prefixes='#', interpolation=None, inline_comment_prefixes=None)
config.read('config.ini')
print(config['dummy']['key'])
# output: 'I am a multiline\nbeing again part'
# expected output:  'I am a multiline\n# multiline part which is not considered but should be\nbeing again part''

Therefore, I would propose to add a new parameter allow_comment_in_value (default False) in the ConfigParser class to support such scenarios. Please note that in this scenario the comment_prefixes is set to '#' and any interpolation is disabled!

Thanks and best regards!

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Comienza con el punto de entrada de ConfigParser y reproduce el comportamiento usando el ejemplo config.ini y test.py del issue. Rastrea cómo se gestionan comment_prefixes y los valores multilínea, y después añade cobertura de pruebas para la opción propuesta. Se considera terminado cuando el comentario indentado se conserva en el valor multilínea, mientras que el comportamiento existente permanece sin cambios de forma predeterminada.