fix: swap cp’s short -r and alias -R recursive options

the only implementable portion of #6223 is “to switch `-R` and `-r`
to `-r` being the alias because `-R` is the POSIX flag”

https://github.com/uutils/coreutils/issues/6223#issuecomment-2054097049

Signed-off-by: Lucas Larson <LucasLarson@riseup.net>

src/uu/cp/src/cp.rs

@@ -475,8 +475,8 @@ pub fn uu_app() -> Command {
         )
         .arg(
             Arg::new(options::RECURSIVE)
-                .short('r')
-                .visible_short_alias('R')
+                .short('R')
+                .visible_short_alias('r')
                 .long(options::RECURSIVE)
                 // --archive sets this option
                 .help("copy directories recursively")