Remove unecessery types changes

Author: mtk3d

src/Collection/Iterator.php

@@ -110,17 +110,20 @@ public function current()
         return $this->current->head();
     }
 
-    public function key(): mixed
+    /**
+     * @return int
+     */
+    public function key()
     {
         return $this->index;
     }
 
-    public function valid(): bool
+    public function valid()
     {
         return $this->hasNext();
     }
 
-    public function rewind(): void
+    public function rewind()
     {
         $this->current = $this->traversable;
     }

src/Collection/Iterator/CompositeIterator.php

@@ -72,7 +72,7 @@ public function next()
         return $this->current->next();
     }
 
-    public function rewind(): void
+    public function rewind()
     {
         $this->iterators->rewind();
         $this->current = $this->iterators->current();

src/Collection/Iterator/EmptyIterator.php

@@ -23,7 +23,10 @@ public function hasNext(): bool
         return false;
     }
 
-    public function next(): void
+    /**
+     * @return void
+     */
+    public function next()
     {
         throw new NoSuchElementException();
     }

src/Collection/Iterator/MapIterator.php

@@ -24,7 +24,7 @@ public function __construct(array $map)
     /**
      * @return int|string|null
      */
-    public function key(): mixed
+    public function key()
     {
         return key($this->map);
     }
@@ -34,7 +34,7 @@ public function current()
         return current($this->map);
     }
 
-    public function rewind(): void
+    public function rewind()
     {
         reset($this->map);
     }
@@ -53,7 +53,7 @@ public function next()
         return $next;
     }
 
-    public function valid(): bool
+    public function valid()
     {
         return key($this->map) !== null;
     }

src/Collection/Traversable.php

@@ -295,7 +295,7 @@ public function count(callable $predicate): int
     /**
      * @return Iterator<T>
      */
-    public function getIterator(): Iterator
+    public function getIterator()
     {
         return $this->iterator();
     }