doc: replace const / var with let

PR-URL: #30446
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: duncanhealy

test/parallel/test-vm-function-declaration.js

@@ -28,17 +28,22 @@ const o = vm.createContext({ console });
 
 // Function declaration and expression should both be copied to the
 // sandboxed context.
-letcode='var a = function() {};\n';
+letcode='let a = function() {};\n';
 code+='function b(){}\n';
+code+='var c = function() {};\n';
+code+='var d = () => {};\n';
+code+='let e = () => {};\n';
 
 // Grab the global b function as the completion value, to ensure that
 // we are getting the global function, and not some other thing
 code+='(function(){return this})().b;\n';
 
 constres=vm.runInContext(code,o,'test');
-
 assert.strictEqual(typeofres,'function');
 assert.strictEqual(res.name,'b');
-assert.strictEqual(typeofo.a,'function');
+assert.strictEqual(typeofo.a,'undefined');
 assert.strictEqual(typeofo.b,'function');
+assert.strictEqual(typeofo.c,'function');
+assert.strictEqual(typeofo.d,'function');
+assert.strictEqual(typeofo.e,'undefined');
 assert.strictEqual(res,o.b);