(yegor256#1572) Generify Fallback parameter of ScalarWithFallback

Co-authored-by: Victor Noël <[email protected]>

Author: DmitryBarskov

src/main/java/org/cactoos/func/FuncWithFallback.java

@@ -100,7 +100,7 @@ public final class FuncWithFallback<X, Y> implements Func<X, Y> {
     /**
      * The fallbacks.
      */
-    private final Iterable<Fallback<? extends Y>> fallbacks;
+    private final Iterable<? extends Fallback<? extends Y>> fallbacks;
 
     /**
      * Ctor.
@@ -119,7 +119,7 @@ public FuncWithFallback(final Func<? super X, ? extends Y> fnc,
      * @param fbks The fallbacks
      */
     public FuncWithFallback(final Func<? super X, ? extends Y> fnc,
-        final Iterable<Fallback<? extends Y>> fbks) {
+        final Iterable<? extends Fallback<? extends Y>> fbks) {
         this.func = fnc;
         this.fallbacks = fbks;
     }

src/main/java/org/cactoos/scalar/ScalarWithFallback.java

@@ -54,7 +54,7 @@ public final class ScalarWithFallback<T> implements Scalar<T> {
     /**
      * The fallback.
      */
-    private final Iterable<Fallback<? extends T>> fallbacks;
+    private final Iterable<? extends Fallback<? extends T>> fallbacks;
 
     /**
      * Ctor.
@@ -75,7 +75,7 @@ public ScalarWithFallback(
      * @param fbks Fallbacks
      */
     public ScalarWithFallback(final Scalar<T> origin,
-        final Iterable<Fallback<? extends T>> fbks) {
+        final Iterable<? extends Fallback<? extends T>> fbks) {
         this.origin = origin;
         this.fallbacks = fbks;
     }