cleanup: use implicit generic type with diamond operator

src/main/java/client/command/commands/gm2/IdCommand.java

@@ -73,7 +73,7 @@ public class IdCommand extends Command {
         if (!handbookDirectory.containsKey(type)) {
             throw new IdTypeNotSupportedException();
         }
-        itemMap.put(type, new HashMap<String, String>());
+        itemMap.put(type, new HashMap<>());
         BufferedReader reader = new BufferedReader(new FileReader(handbookDirectory.get(type)));
         String line;
         while ((line = reader.readLine()) != null) {