Preserve Markdown callout blockquote lines in docbuilder style docstring formatting + merge body

[qgallouedec]

Same as #756, but wraps the text:

from doc_builder.style_doc import style_docstring


test_docstring = """Function description

Params:
    x (`int`): This is x.

> [!NOTE]
> This is a note.
> This is still part of the note.
"""

print(style_docstring(test_docstring, 119)[0])

$ python demo.py 
Function description

Params:
    x (`int`): This is x.

> [!NOTE]
> This is a note. This is still part of the note.

from doc_builder.style_doc import style_docstring


text = """Function description

Params:
    x (`int`): This is x.

> [!NOTE]
> This is a very very very very long note that should be wrapped and keep the prefix.
"""
print(style_docstring(text, 32)[0])

Function description

Params:
    x (`int`): This is x.

> [!NOTE]
> This is a very very very very
> long note that should be
> wrapped and keep the prefix.

[albertvillanova]

Are you sure we are keeping the expected behavior as needed in huggingface/trl#5172:

> [!NOTE]
> We want to keep the lists:
> - Item 1
> - Item 2