AK: Defer to Traits<T> for equality comparison in container templates.

This is prep work for supporting HashMap with NonnullRefPtr<T> as values.
It's currently not possible because many HashTable functions require being
able to default-construct the value type.

Kernel/FileSystem/DiskBackedFileSystem.cpp

@@ -15,7 +15,7 @@ struct BlockIdentifier {
 namespace AK {
 
 template<>
-struct Traits<BlockIdentifier> {
+struct Traits<BlockIdentifier> : public GenericTraits<BlockIdentifier> {
     static unsigned hash(const BlockIdentifier& block_id) { return pair_int_hash(block_id.fsid, block_id.index); }
     static void dump(const BlockIdentifier& block_id) { kprintf("[block %02u:%08u]", block_id.fsid, block_id.index); }
 };