Add #allow attribute to suppress FP #7698

Author: Qwaz

clippy_lints/src/uninit_vec.rs

@@ -71,6 +71,8 @@ fn handle_uninit_vec_pair(
         // Check T of Vec<T>
         if !is_uninit_value_valid_for_ty(cx, substs.type_at(0));
         then {
+            // FIXME: false positive #7698
+            #[allow(clippy::collapsible_span_lint_calls)]
             span_lint_and_then(
                 cx,
                 UNINIT_VEC,