Restore printing the url to GraphiQL (#3248)

Author: KyleAMathews

packages/gatsby/src/commands/develop.js

@@ -302,6 +302,13 @@ module.exports = async (program: any) => {
       console.log(`  ${urls.localUrlForTerminal}`)
     }
 
+    console.log()
+    console.log(
+      `View GraphiQL, an in-browser IDE, to explore your site's data and schema`
+    )
+    console.log()
+    console.log(`  ${urls.localUrlForTerminal}___graphql`)
+
     console.log()
     console.log(`Note that the development build is not optimized.`)
     console.log(