[docs] update env example (#4078)

Author: benceruleanlu

.env_example

@@ -29,3 +29,7 @@ DISABLE_TEMPLATES_PROXY=false
 # If playwright tests are being run via vite dev server, Vue plugins will
 # invalidate screenshots.  When `true`, vite plugins will not be loaded.
 DISABLE_VUE_PLUGINS=false
+
+# Algolia credentials required for developing with the new custom node manager.
+ALGOLIA_APP_ID=4E0RO38HS8
+ALGOLIA_API_KEY=684d998c36b67a9a9fce8fc2d8860579