Permit `/` to be used in place of `-` for short commands

[delphidabbler]

On Windows / is often used to introduce and command line parameter.

For example /c would be an alias of -c.

Since / is not used for Linux command line parameters, this alias shouldn't be available on Linux.

[delphidabbler]

It's far more work to implement with the current implementation of TParams than any likely benefit.