doc: fix header level typo

PR-URL: #14707
Refs: #12756
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Daijiro Wachi <[email protected]>
Reviewed-By: Sakthipriyan Vairamani <[email protected]>

Author: refack

doc/api/cli.md

@@ -185,7 +185,7 @@ added: v8.0.0
 Enable loading native modules compiled with the ABI-stable Node.js API (N-API)
 (experimental).
 
-## `--abort-on-uncaught-exception`
+### `--abort-on-uncaught-exception`
 <!-- YAML
 added: v0.10
 -->