Document that you can use just the username and repo in gatsby new … (

gatsbyjs#13463)

* Document that you can use just the username and repo in `gatsby new` gatsbyjs#13455

* Fix accidental space

docs/docs/starters.md

@@ -6,16 +6,22 @@ The Gatsby CLI tool lets you install “starters”. These are boilerplate Gatsb
 
 `gatsby new` helps you start your project by cloning the boilerplate, installing dependencies, and clearing Git history.
 
-When creating a new site, you can optionally specify a starter to base your new site on e.g.
+When creating a new site, you can optionally specify a starter to base your new site on, either with the `[URL]` of the `[GIT_USER_NAME/REPO]` e.g.
 
 `gatsby new [SITE_DIRECTORY] [URL_OF_STARTER_GITHUB_REPO]`
+or
+`gatsby new [SITE_DIRECTORY] [GIT_USER_NAME/REPO]`
 
 For example, to quickly create a blog using Gatsby, you could install the Gatsby Starter Blog by running:
 
 `gatsby new blog https://github.com/gatsbyjs/gatsby-starter-blog`
 
 This downloads the files and initializes the site by running `npm install`
 
+Or, you can use the `[GIT_USER_NAME/REPO]`
+
+`gatsby new blog gatsbyjs/gatsby-starter-blog`
+
 If you don't specify a custom starter, your site will be created from the [default starter](https://github.com/gatsbyjs/gatsby-starter-default).
 
 > Learn [how to make a starter](/docs/creating-a-starter/) in the Gatsby docs. Starters can be created for your team(s) only, or distributed to the broader community. It's up to you!