doc: do not use weak MODP group in example

As a first, small step toward deprecating modp1, stop using it in an
example that users might copy.

Refs: #44539
PR-URL: #44585
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: theanarkh <theratliter@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/crypto.md

@@ -1175,12 +1175,12 @@ or `setPrivateKey()` methods.
 
 ```mjs
 const { createDiffieHellmanGroup } = await import('node:crypto');
-const dh = createDiffieHellmanGroup('modp1');
+const dh = createDiffieHellmanGroup('modp16');
 ```
 
 ```cjs
 const { createDiffieHellmanGroup } = require('node:crypto');
-const dh = createDiffieHellmanGroup('modp1');
+const dh = createDiffieHellmanGroup('modp16');
 ```
 
 The following groups are supported: