jobqueue: Document Title as valid param type for compat

Follows-up 9b4938c40d.

This should fix build failures that are preventing merges
in repos where Phan is finding Job::__construct(string, Title)
where it currently fails as follows:

 CompileArticleMetadataJob.php:11
 PhanTypeMismatchArgument Argument 2 (params) is …\Title|string but
 \Job::__construct() takes array

As Phan is reading the php doc I guess.

Change-Id: I94b442f06b6858d136546bf22f2465cf8f071ab0

includes/jobqueue/Job.php

@@ -65,7 +65,7 @@ abstract class Job implements IJobSpecification {
 	 * Create the appropriate object to handle a specific job
 	 *
 	 * @param string $command Job command
-	 * @param array $params Job parameters
+	 * @param array|Title $params Job parameters
 	 * @throws InvalidArgumentException
 	 * @return Job
 	 */