shuf: fix error message text on negative-sized ranges

Found by @cakebaker:
#6011 (comment)

Author: BenWiederhake

src/uu/shuf/src/shuf.rs

@@ -471,7 +471,11 @@ fn parse_range(input_range: &str) -> Result<RangeInclusive<usize>, String> {
         let end = to
             .parse::<usize>()
             .map_err(|_| format!("invalid input range: {}", to.quote()))?;
-        Ok(begin..=end)
+        if begin <= end || begin == end + 1 {
+            Ok(begin..=end)
+        } else {
+            Err(format!("invalid input range: {}", input_range.quote()))
+        }
     } else {
         Err(format!("invalid input range: {}", input_range.quote()))
     }

tests/by-util/test_shuf.rs

@@ -762,7 +762,11 @@ fn test_range_empty() {
 
 #[test]
 fn test_range_empty_minus_one() {
-    new_ucmd!().arg("-i5-3").succeeds().no_output();
+    new_ucmd!()
+        .arg("-i5-3")
+        .fails()
+        .no_stdout()
+        .stderr_only("shuf: invalid input range: '5-3'\n");
 }
 
 #[test]
@@ -792,5 +796,5 @@ fn test_range_repeat_empty_minus_one() {
         .arg("-ri5-3")
         .fails()
         .no_stdout()
-        .stderr_only("shuf: no lines to repeat\n");
+        .stderr_only("shuf: invalid input range: '5-3'\n");
 }