Fix a typo in the readme (#1595)

README.md

@@ -5,7 +5,7 @@ Printing since 1440.
 
 ![Text block](https://wpcoredesign.mystagingwebsite.com/gutenberg/gutenberg.png)
 
-This is the development hub for the <a href="https://make.wordpress.org/core/2017/01/04/focus-tech-and-design-leads/">editor focus in core</a>. Gutenberg is the project name. If you want the latest release for your WordPress, <a href="https://wordpress.org/plugins/gutenberg/">download Gutenberg from the WordPress.org plugins repository</a>. Conversations and discussions take place in #core-editor on <a href="https://make.wordpress.org/chat/">the core WordPress Slack</a>. This is our kickoff goal:
+This is the development hub for the <a href="https://make.wordpress.org/core/2017/01/04/focus-tech-and-design-leads/">editor focus in a core</a>. Gutenberg is the project name. If you want the latest release for your WordPress, <a href="https://wordpress.org/plugins/gutenberg/">download Gutenberg from the WordPress.org plugins repository</a>. Conversations and discussions take place in #core-editor on <a href="https://make.wordpress.org/chat/">the core WordPress Slack</a>. This is our kickoff goal:
 
 > The editor will endeavour to create a new page and post building experience that makes writing rich posts effortless, and has “blocks” to make it easy what today might take shortcodes, custom HTML, or “mystery meat” embed discovery. — Matt Mullenweg