Fix failing test with unicode-lines feature (#3455)

helix-core/src/line_ending.rs

@@ -305,8 +305,17 @@ mod line_ending_tests {
     fn line_end_char_index_rope_slice() {
         let r = Rope::from_str("Hello\rworld\nhow\r\nare you?");
         let s = &r.slice(..);
-        assert_eq!(line_end_char_index(s, 0), 11);
-        assert_eq!(line_end_char_index(s, 1), 15);
-        assert_eq!(line_end_char_index(s, 2), 25);
+        #[cfg(not(feature = "unicode-lines"))]
+        {
+            assert_eq!(line_end_char_index(s, 0), 11);
+            assert_eq!(line_end_char_index(s, 1), 15);
+            assert_eq!(line_end_char_index(s, 2), 25);
+        }
+        #[cfg(feature = "unicode-lines")]
+        {
+            assert_eq!(line_end_char_index(s, 0), 5);
+            assert_eq!(line_end_char_index(s, 1), 11);
+            assert_eq!(line_end_char_index(s, 2), 15);
+        }
     }
 }