fido2 key filename should remove colon in filename

[jpph]

Prerequisites

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Steps to reproduce

when using ssh-keygen -K, usualy the keyname is somesing like hostname:user.pub

ssh-keygen will create 2 file with this name, one with no extention and one with .pub.

It fails on windows because of the colon. The -f option doesn't work because it is not taken in account with the -K option.

It works fine if using ssh delivered with git for windows (using bash.exe , it will put the unicode code of : in the file name like this : id_ed25519_sk_rk_yubi1user1.pub

Expected behavior

replace : with _ so filename can be created in windows

Actual behavior

leave an empty file with filename truncated before the :

Error details

Environment data

Name                           Value
----                           -----
PSVersion                      5.1.26100.7462
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.26100.7462
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Version

OpenSSH_for_Windows_9.5p2, LibreSSL 3.8.2

Visuals

No response