Add `exist_okay` parameter to `Path.symlink_to()`

Feature or enhancement

Proposal:

The same way Path.mkdir(exist_ok=True) and Path.touch(exist_ok=True) work.
Overriding an existing symbolic link should not throw an error if it's expected behaviour.

Actual behaviour:

path_to_sym = Path("existing_symlink_file")
path_to_sym.symlink_to(Path("../other_location"), target_is_directory=True)

[Errno 17] File exists: '../original_location' -> '../other_location'

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

See also:
#132416
https://github.com/python/cpython/issues/64173
https://github.com/python/cpython/issues/105919

Linked PRs

• gh-157659

开始之前，查看关联的 PR gh-157659 以及相关 issue #132416、#64173 和 #105919。验证当目标是现有符号链接时，提议的参数应如何工作，包括示例情况；当预期的覆盖操作不再引发错误时，该 issue 即完成。