Docs: Document directory support in `FTP/SSH2` filesystem `::move()` methods.

[costdev]

This is a follow-up to #57375.

With directory support added to WP_Filesystem_Direct::move() in #57375, we should update the documentation of the other filesystem ::move() methods to document their inherent directory support.

WP_Filesystem_FTPext::move()

WP_Filesystem_FTPext::move() calls ​ftp_rename() - "Renames a file or a directory on the FTP server"


WP_Filesystem_ftpsockets::move()

WP_Filesystem_ftpsockets::move() calls ​$this->ftp->rename - Uses RNFR/RNTO which work on files and directories.


WP_Filesystem_SSH2::move()

WP_Filesystem_SSH2::move() calls ​ssh2_sftp_rename Ultimately calls ​sftp_rename (C).

While this states "Rename a file on the remote server", the "Removing and Renaming Files" section at ​http://www.openssh.com/txt/draft-ietf-secsh-filexfer-02.txt states:

Files (and directories) can be renamed using the SSH_FXP_RENAME message.

This is what libssh2's sftp_rename function uses: ​Ref (C).

Trac ticket: https://core.trac.wordpress.org/ticket/57604

[audrasjb]

This sounds good, but we need to wait for #57375 to be committed, right?

(unrelated, but it would be nice to have a way to clearly indicate tickets dependencies)

[flixos90]

@audrasjb Correct. Technically there is no dependency on each other, but makes more sense to commit #57375 first.

@SergeyBiryukov Since you're owning #57375, could you commit this one afterwards as well?

[azaozz]

In 55205:

Docs: Document directory support in FTP/SSH2 filesystem ::move() methods.

Props: costdev, flixos90, audrasjb.
Fixes: #57604.

Committed: https://core.trac.wordpress.org/changeset/55205