test: prepare for consistent comma-dangle lint rule

Make changes so that tests will pass when the comma-dangle settings
applied to the rest of the code base are also applied to tests.

PR-URL: https://github.com/nodejs/node/pull/37930
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Derek Lewis <DerekNonGeneric@inf.is>

test/parallel/test-eslint-documented-errors.js

@@ -14,7 +14,7 @@ new RuleTester().run('documented-errors', rule, {
   valid: [
     `
       E('ERR_ASSERTION', 'foo');
-    `
+    `,
   ],
   invalid: [
     {
@@ -30,8 +30,8 @@ new RuleTester().run('documented-errors', rule, {
           message:
             `doc/api/errors.md does not have an anchor for "${invalidCode}"`,
           line: 2
-        }
+        },
       ]
-    }
+    },
   ]
 });