Fix external-assertions snapshot for Node.js 20.11

This assumes test are run with at least that minor version.

Author: novemberborn

test/external-assertions/snapshots/test.js.md

@@ -109,9 +109,14 @@ Generated by [AVA](https://avajs.dev).
     ␊
       Assertion failed: ␊
     ␊
-      false == true␊
+      The expression evaluated to a falsy value:␊
+    ␊
+        assert(false)␊
+    ␊
+      AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:␊
+    ␊
+        assert(false)␊
     ␊
-      AssertionError [ERR_ASSERTION]: false == true␊
           at ---␊
           at ---␊
           at ---␊