Short-circuit the word and treesitter object movement commands

The loop always iterates the number of times the user specified even
if the beginning/end of the document is reached.

For an extreme demonstration try the following commands, Helix will
hang for several seconds.
100000000w
100000000]c

helix-core/src/movement.rs

@@ -227,9 +227,15 @@ fn word_move(slice: RopeSlice, range: Range, count: usize, target: WordMotionTar
     };
 
     // Do the main work.
-    (0..count).fold(start_range, |r, _| {
-        slice.chars_at(r.head).range_to_target(target, r)
-    })
+    let mut r = start_range;
+    for _ in 0..count {
+        let tmp = slice.chars_at(r.head).range_to_target(target, r);
+        if r == tmp {
+            break;
+        }
+        r = tmp;
+    }
+    r
 }
 
 pub fn move_prev_paragraph(
@@ -523,7 +529,14 @@ pub fn goto_treesitter_object(
         // head of range should be at beginning
         Some(Range::new(start_char, end_char))
     };
-    (0..count).fold(range, |range, _| get_range(range).unwrap_or(range))
+    let mut last_range = range;
+    for _ in 0..count {
+        match get_range(last_range) {
+            Some(r) if r != last_range => last_range = r,
+            _ => break,
+        }
+    }
+    last_range
 }
 
 #[cfg(test)]