Support _netrc files for windows

[jurkov]

It is quite strange but on Windows the .netrc file has the name _netrc.
Please add _netrc support.

Sources:
https://stackoverflow.com/questions/6031214/git-how-to-use-netrc-file-on-windows-to-save-user-and-password
https://www.labkey.org/Documentation/wiki-page.view?name=netrc
https://github.com/curl/curl/blob/6e4b7abfd3bef38130598b7f62289881f448a13c/docs/cmdline-opts/netrc.md?plain=1#L28

[gribouille]

Ok, _netrc replaces .netrc on Windows or it's an alternative ?

[T-256]

Curl:

On Windows two filenames in the home directory are checked: .netrc and _netrc, preferring the former.

Select each one will be correct. when both available, _netrc preferred.