Fixed a typo. (#52562)

packages/flutter/lib/src/material/list_tile.dart

@@ -1416,7 +1416,7 @@ class _RenderListTile extends RenderBox {
     // This attempts to implement the redlines for the vertical position of the
     // leading and trailing icons on the spec page:
     //   https://material.io/design/components/lists.html#specs
-    // The interpretation for these red lines is as follows:
+    // The interpretation for these redlines is as follows:
     //  - For large tiles (> 72dp), both leading and trailing controls should be
     //    a fixed distance from top. As per guidelines this is set to 16dp.
     //  - For smaller tiles, trailing should always be centered. Leading can be