SRI: mention the modifications to fetch()

As suggested by @annevk

Author: Francois Marier

specs/subresourceintegrity/spec.markdown

@@ -29,9 +29,9 @@ impunity. Ideally, authors would not only be able to pin the keys of a
 server, but also pin the _content_, ensuring that an exact representation of
 a resource, and _only_ that representation, loads and executes.
 
-This document specifies such a validation scheme, extending two HTML
-elements with an `integrity` attribute that contains a cryptographic hash of
-the representation of the resource the author expects to load. For instance,
+This document specifies such a validation scheme, extending two HTML elements
+and the `fetch()` API with an `integrity` attribute that contains a cryptographic hash
+of the representation of the resource the author expects to load. For instance,
 an author may wish to load some framework from a shared server rather than hosting it
 on their own origin. Specifying that the _expected_ SHA-256 hash of
 `https://example.com/example-framework.js`