CircularDeque: Correctly pass args to enqueue

Problem:
- Using regular functions rather than function templates results in
  the arguments not being deduced. This then requires the same
  function to be written multiple times and for `move` to be used
  rather than `forward`.

Solution:
- Collapse multiple function overloads to a single function template
  with a deduced argument. This allows the argument to be a forwarding
  reference and bind to either an l-value or r-value and forward the
  value.

AK/CircularDeque.h

@@ -35,7 +35,8 @@ namespace AK {
 template<typename T, size_t Capacity>
 class CircularDeque : public CircularQueue<T, Capacity> {
 public:
-    void enqueue_begin(T&& value)
+    template<typename U = T>
+    void enqueue_begin(U&& value)
     {
         const auto new_head = (this->m_head - 1 + Capacity) % Capacity;
         auto& slot = this->elements()[new_head];
@@ -44,15 +45,10 @@ public:
         else
             ++this->m_size;
 
-        new (&slot) T(move(value));
+        new (&slot) T(forward<U>(value));
         this->m_head = new_head;
     }
 
-    void enqueue_begin(const T& value)
-    {
-        enqueue_begin(T(value));
-    }
-
     T dequeue_end()
     {
         ASSERT(!this->is_empty());