docs(README.md): link to APIs used

README.md

@@ -5,10 +5,10 @@
 
 Quicklink attempts to make navigations to subsequent pages load faster. It:
 
-* **Detects links within the viewport** (using `IntersectionObsever`)
-* **Waits until the browser is idle** (using `requestIdleCallback`)
+* **Detects links within the viewport** (using [Intersection Observer](https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API))
+* **Waits until the browser is idle** (using [requestIdleCallback](https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback))
 * **Checks if the user isn't on a slow connection** (using `navigator.connection.effectiveType`) or has data-saver enabled (using `navigator.connection.saveData`)
-* **Prefetches URLs to the links** (using `<link rel=prefetch>` or XHR). Provides some control over the request priority (can switch to `fetch()` if supported).
+* **Prefetches URLs to the links** (using [<link rel=prefetch>](https://www.w3.org/TR/resource-hints/#prefetch) or XHR). Provides some control over the request priority (can switch to `fetch()` if supported).
 
 ## Installation