Fix for filename collision in on.mdx (#926)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: MissEvelynLily

src/routes/reference/reactive-utilities/data.json

@@ -10,7 +10,7 @@
 		"map-array.mdx",
 		"merge-props.mdx",
 		"observable.mdx",
-		"on.mdx",
+		"on-util.mdx",
 		"run-with-owner.mdx",
 		"split-props.mdx",
 		"start-transition.mdx",