Everywhere: Include HashMap only where it's actually used

Author: https://github.com/shlyakpavel
Commit: 6f81b80114
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2839

Libraries/LibUnicode/CurrencyCode.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/HashMap.h>
 #include <LibUnicode/CurrencyCode.h>
 
 namespace Unicode {