chore: Add restart server inline docs

Author: tomtev

gridsome.config.js

@@ -1,7 +1,10 @@
 // This is where project configuration and installed plugin options are located. 
 // Learn more: https://gridsome.org/docs/config
 
+// Changes here requires a server restart to work properly.
+// To restart press CTRL + C in terminal and run `gridsome develop`
+
 module.exports = {
   siteName: 'Gridsome',
   plugins: []
-}
+}