Soft deprecated EditPage::submit to avoid new use

Currently this has no usages.
::edit can be called directly

Change-Id: I892e3de61c0513dc186d0f35e05107ed7136447d

includes/EditPage.php

@@ -498,6 +498,9 @@ class EditPage {
 		$this->enableApiEditOverride = $enableOverride;
 	}
 
+	/**
+	 * @deprecated since 1.29, call edit directly
+	 */
 	function submit() {
 		$this->edit();
 	}