cat: fix -b and -n anti-symmetry

src/uu/cat/src/cat.rs

@@ -250,7 +250,8 @@ pub fn uu_app() -> Command {
                 .short('b')
                 .long(options::NUMBER_NONBLANK)
                 .help("number nonempty output lines, overrides -n")
-                .overrides_with(options::NUMBER)
+                // Note: This MUST NOT .overrides_with(options::NUMBER)!
+                // In clap, overriding is symmetric, so "-b -n" counts as "-n", which is not what we want.
                 .action(ArgAction::SetTrue),
         )
         .arg(

tests/by-util/test_cat.rs

@@ -438,7 +438,6 @@ fn test_non_blank_overrides_number() {
 }
 
 #[test]
-#[ignore = "known issue"]
 fn test_non_blank_overrides_number_even_when_present() {
     new_ucmd!()
         .args(&["-n", "-b", "-n"])