SPIGOT-1030: Allow commands.yml to act on aliases

By: md_5 <git@md-5.net>

paper-api/src/main/java/org/bukkit/command/SimpleCommandMap.java

@@ -222,7 +222,7 @@ public class SimpleCommandMap implements CommandMap {
         Map<String, String[]> values = server.getCommandAliases();
 
         for (String alias : values.keySet()) {
-            if (alias.contains(":") || alias.contains(" ")) {
+            if (alias.contains(" ")) {
                 server.getLogger().warning("Could not register alias " + alias + " because it contains illegal characters");
                 continue;
             }