Update m.render_in to is_falling_back (+ unstable field) (#7979)

src/@types/common.ts

@@ -34,3 +34,10 @@ type Prev = [never, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ...0[]];
 
 export type Leaves<T, D extends number = 5> = [D] extends [never] ? never : T extends object ?
     { [K in keyof T]-?: Join<K, Leaves<T[K], Prev[D]>> }[keyof T] : "";
+
+export type RecursivePartial<T> = {
+    [P in keyof T]?:
+    T[P] extends (infer U)[] ? RecursivePartial<U>[] :
+        T[P] extends object ? RecursivePartial<T[P]> :
+            T[P];
+};