doc: deprecate modp1, modp2, and modp5 groups

These MODP groups should not be used by new applications, and existing
applications should attempt to migrate to stronger groups (or different
key exchange mechanisms).

Some applications still rely on these particular groups, so Node.js will
likely maintain support, directly or indirectly, for the foreseeable
future.

Refs: https://github.com/nodejs/node/issues/44539
PR-URL: https://github.com/nodejs/node/pull/44588
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api_assets/style.css

@@ -598,7 +598,8 @@ hr {
   padding-left: 5rem;
 }
 
-#toc .stability_0::after {
+#toc .stability_0::after,
+.deprecated-inline::after {
   background-color: var(--red2);
   color: var(--white);
   content: "deprecated";