GUILD_MESSAGES_SEARCH endpoint preview

https://github.com/discord/discord-api-spec/blob/976faf177d21062f258b116bbbb41b50be24fc0f/specs/openapi_preview.json#L7901

Author: valzargaming

src/Discord/Endpoint.php

@@ -138,6 +138,8 @@ class Endpoint implements EndpointInterface
     public const GUILD_CHANNELS = self::GUILD.'/channels';
     // GET
     public const GUILD_THREADS_ACTIVE = self::GUILD.'/threads/active';
+    // GET
+    public const GUILD_MESSAGES_SEARCH = self::GUILD.'/messages/search';
 
     // GET
     public const GUILD_MEMBERS = self::GUILD.'/members';