docs: Upgrade to Node.js v22

Author: igorlukanin

docs/.nvmrc

@@ -0,0 +1 @@
+22

docs/next.config.mjs

@@ -4,7 +4,7 @@ import remarkFrontmatter from "remark-frontmatter";
 import remarkHtmlKatex from "remark-html-katex";
 import linkEnvironmentVariables from "./plugins/link-environment-variables.mjs";
 
-import redirects from './redirects.json' assert { type: "json" };
+import redirects from './redirects.json' with { type: "json" };
 
 /**
  * @type {import('next').NextConfig}