Remove unused developer docs environment variable check

Author: cursoragent

src/middleware.ts

@@ -1,10 +1,6 @@
 import type {NextRequest} from 'next/server';
 import {NextResponse} from 'next/server';
 
-// This env var is set in next.config.js based on the `NEXT_PUBLIC_DEVELOPER_DOCS` env var at build time
-// a workaround edge middleware not having access to env vars
-const isDeveloperDocs = process.env.DEVELOPER_DOCS_;
-
 export const config = {
   // learn more: https://nextjs.org/docs/pages/building-your-application/routing/middleware#matcher
   matcher: [