docstrings/numpy: Support "ignore __init__ summary" option

[pawamoy]

The mkdocstrings Python handler is able to merge __init__ methods docstrings into their classes' docstrings.
This is nice, but usually __init__ methods just have a summary like "Initialize this [CLASS]." which simply breaks the flow of the merged docstring, especially since it's usually followed by a Parameters section.

This option allows to ignore the summary (while keeping the correct line number in parsing warnings).

griffe/src/griffe/docstrings/google.py

Lines 522 to 534 in 81f0333

	ignore_summary = (
	ignore_init_summary # noqa: WPS222
	and docstring.parent is not None
	and docstring.parent.name == "__init__"
	and docstring.parent.is_function
	and docstring.parent.parent is not None
	and docstring.parent.parent.is_class
	)
	if ignore_summary:
	offset = 2
	else:
	offset = 0