Merge pull request #911 from pra85/patch-1

Fix typos

CONTRIBUTING.md

@@ -8,9 +8,9 @@ Here are some tips to consider and to help you write a great report:
 * `_s` supports Microsoft Internet Explorer 11 and Edge, as well as the latest two versions of all other major browsers.
 * `_s` is backwards compatible with the two versions prior to the current stable version of WordPress.
 * `_s` uses HTML5 markup.
-* We decided not to include translations [[#50](https://github.com/Automattic/_s/pull/50)] beyond the exisiting `_s.pot` file, a RTL stylesheet [[#263](https://github.com/Automattic/_s/pull/263)], or editor styles [[#225](https://github.com/Automattic/_s/pull/225)], as they are likely to change during development of an `_s`-based theme.
+* We decided not to include translations [[#50](https://github.com/Automattic/_s/pull/50)] beyond the existing `_s.pot` file, a RTL stylesheet [[#263](https://github.com/Automattic/_s/pull/263)], or editor styles [[#225](https://github.com/Automattic/_s/pull/225)], as they are likely to change during development of an `_s`-based theme.
 
-## Contibuting code
+## Contributing code
 
 Found a bug you can fix? Fantastic! Patches are always welcome. Here's a few tips for crafting a great pull request: