Add --properties syntax to create command

Author: benwoo1110

src/main/java/org/mvplugins/multiverse/core/commands/CreateCommand.java

@@ -53,7 +53,7 @@ class CreateCommand extends CoreCommand {
     @CommandPermission("multiverse.core.create")
     @CommandCompletion("@empty @environments @flags:groupName=" + Flags.NAME)
     @Syntax("<name> <environment> [--seed <seed> --generator <generator[:id]> --world-type <worldtype> --adjust-spawn "
-            + "--no-structures --biome <biome>]")
+            + "--no-structures --biome <biome> --properties <prop1=value1,prop2=value2,...>]")
     @Description("{@@mv-core.create.description}")
     void onCreateCommand(
             MVCommandIssuer issuer,
@@ -68,7 +68,7 @@ void onCreateCommand(
 
             @Optional
             @Syntax("[--seed <seed> --generator <generator[:id]> --world-type <worldtype> --adjust-spawn "
-                    + "--no-structures --biome <biome>]")
+                    + "--no-structures --biome <biome> --properties <prop1=value1,prop2=value2,...>]")
             @Description("{@@mv-core.create.flags.description}")
             String[] flagArray) {
         ParsedCommandFlags parsedFlags = flags.parse(flagArray);