RFR: 8302789: (fs) File.copy should include unsupported copy option in exception message

[Brian Burkhalter]

On Fri, 17 Feb 2023 20:42:49 GMT, Christian Stein <cstein at openjdk.org> wrote:

> This PR also fixes the exception message for unsupported move options.

The same change could be made in `unix/classes/sun/nio/fs/UnixFileSystem.java`. If that change is made in this PR, then the issue should be updated to have the OS be blank or generic instead of `windows`. The copyright year of `WindowsFileCopy` needs to be updated, as would that of `UnixFileSystem` if that class is similarly changed.

Also the issue summary and this PR's name should be changed to reference `Files::copy` rather than `File::copy`.

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PR: https://git.openjdk.org/jdk/pull/12625