tr: enable passing -s multiple times

src/uu/tr/src/tr.rs

@@ -191,7 +191,8 @@ pub fn uu_app() -> Command {
                      listed in the last specified SET, with a single occurrence \
                      of that character",
                 )
-                .action(ArgAction::SetTrue),
+                .action(ArgAction::SetTrue)
+                .overrides_with(options::SQUEEZE),
         )
         .arg(
             Arg::new(options::TRUNCATE_SET1)

tests/by-util/test_tr.rs

@@ -182,7 +182,16 @@ fn test_squeeze() {
     new_ucmd!()
         .args(&["-s", "a-z"])
         .pipe_in("aaBBcDcc")
-        .run()
+        .succeeds()
+        .stdout_is("aBBcDc");
+}
+
+#[test]
+fn test_squeeze_multi() {
+    new_ucmd!()
+        .args(&["-ss", "-s", "a-z"])
+        .pipe_in("aaBBcDcc")
+        .succeeds()
         .stdout_is("aBBcDc");
 }
 
@@ -191,7 +200,16 @@ fn test_squeeze_complement() {
     new_ucmd!()
         .args(&["-sc", "a-z"])
         .pipe_in("aaBBcDcc")
-        .run()
+        .succeeds()
+        .stdout_is("aaBcDcc");
+}
+
+#[test]
+fn test_squeeze_complement_multi() {
+    new_ucmd!()
+        .args(&["-scsc", "a-z"]) // spell-checker:disable-line
+        .pipe_in("aaBBcDcc")
+        .succeeds()
         .stdout_is("aaBcDcc");
 }