fix formatting

src/vec-insert-remove.md

@@ -22,8 +22,8 @@ pub fn insert(&mut self, index: usize, elem: T) {
     unsafe {
         // ptr::copy(src, dest, len): "copy from src to dest len elems"
         ptr::copy(self.ptr.as_ptr().offset(index as isize),
-                    self.ptr.as_ptr().offset(index as isize + 1),
-                    self.len - index);
+                  self.ptr.as_ptr().offset(index as isize + 1),
+                  self.len - index);
         ptr::write(self.ptr.as_ptr().offset(index as isize), elem);
         self.len += 1;
     }