make Command.create() return existing instance for known commands

When the `Command.create()` method is used to create a `Command` instance
for a known command (not recommended, but also not forbidden), it used to
return a generic instance that doesn't know anything about where the keys
are in the command. Such generic instance is unusable with Redis cluster,
because the target node will be selected randomly, not based on the key,
and there's high chance such command will result in the `MOVED` redirect.

With this commit, `Command.create()` will return a pre-existing static
instance for known commands, which is key-aware and works with Redis cluster.

src/main/java/io/vertx/redis/client/Command.java

@@ -27,7 +27,7 @@
  * <b>Auto generated</b> API Commands to interact with REDIS.
  *
  * @author <a href="mailto:[email protected]">Paulo Lopes</a>
- * @version redis_version:7.0.6
+ * @version redis_version:7.0.12
  */
 @VertxGen
 public interface Command {
@@ -427,11 +427,15 @@ public interface Command {
 
   /**
    * Generic command generator for extensions.
+   * <p>
+   * To avoid inconsistent behavior, when {@code command} is one of the known commands
+   * for which a static instance exists, the static instance is returned.
    *
    * @param command command name
    * @return the cacheable immutable command instance
    */
   static Command create(String command) {
-    return new CommandImpl(command, -1, null, false, true);
+    Command known = CommandMap.getKnownCommand(command);
+    return known != null ? known : new CommandImpl(command, -1, null, false, true);
   }
 }