Merge pull request #46 from WICG/marcoscaceres-patch-1

Add link to spec

Author: mgiuca

README.md

@@ -8,9 +8,8 @@ images to an arbitrary destination of the user's choice:
 ```js
 navigator.share({title: 'Example Page', url: 'https://example.com'});
 ```
-
+* [Specification](https://wicg.github.io/web-share/)
 * [Explainer document](docs/explainer.md), a high-level overview of the proposal.
-* [Interface document](docs/interface.md), an informal spec.
 * [Native integration survey](docs/native.md), for platform-specific matters.
 
 This is a product of the [Ballista