Expand CommandHelpTests

Add tests for CommandAPI#454, CommandAPI#537, and CommandAPI@f9c5fce. Just generally ensure code coverage for help generation.

Pulled repetitive logic into `CommandHelpTests#assertHelpTopicCreated` and `TestBase#enableServer`

Also, small change: The alias list in an alias help topic had a redundant `ChatColor.WHITE` character

Author: willkroboth

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/CommandAPIBukkit.java

@@ -422,7 +422,7 @@ void updateHelpForCommands(List<RegisteredCommand> commands) {
 					aliases.add(command.commandName());
 					aliases.remove(alias);
 
-					currentAliasSb.append(ChatColor.WHITE).append(String.join(", ", aliases));
+					currentAliasSb.append(String.join(", ", aliases));
 
 					// Don't override the plugin help topic
 					commandPrefix = generateCommandHelpPrefix(alias);