doc: fix linter issue

aduh95 · danielleadams · commit ebc6f410725e · 2021-03-16T08:55:25.000-04:00
PR-URL: #37657 Reviewed-By: Darshan Sen <raisinten@gmail.com> Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
diff --git a/doc/api/assert.md b/doc/api/assert.md
@@ -112,7 +112,7 @@ Legacy assertion mode uses the [Abstract Equality Comparison][] in:
 
 To use legacy assertion mode:
 
-```cjs
+```mjs
 import assert from 'assert';
 ```
 
