[web-animations-1] Fix some broken links

Fixes w3c#8382.

Author: birtles

web-animations-1/Overview.bs

@@ -120,14 +120,10 @@ Markup Shorthands: markdown yes
 Include Mdn Panels: no
 </pre>
 <pre class="anchors">
-urlPrefix: https://heycam.github.io/webidl/#dfn-; type: dfn; spec: webidl
-    text: present
-    text: platform object
+urlPrefix: https://webidl.spec.whatwg.org/#dfn-; type: dfn; spec: webidl
     text: nullable; url: nullable-type
-    text: throw
-    text: thrown; url: throw
     text: convert ecmascript to idl value
-urlPrefix: https://heycam.github.io/webidl/; type: dfn; spec: webidl
+urlPrefix: https://webidl.spec.whatwg.org/; type: dfn; spec: webidl
     text: a new promise
     text: create a new resolved Promise; url: a-promise-resolved-with
     text: [EnforceRange]; url: EnforceRange
@@ -173,9 +169,6 @@ urlPrefix: https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.htm
     text: run the animation frame callbacks
 urlPrefix: https://html.spec.whatwg.org/multipage/embedded-content.html; type: dfn; spec: html
     text: media element
-urlPrefix: https://w3c.github.io/hr-time/; spec: highres-time
-    text: time origin; type: dfn
-    text: DOMHighResTimeStamp; type: interface
 urlPrefix: https://dom.spec.whatwg.org/; type: dfn; spec: dom
     text: create an event; url: concept-event-create
     text: dispatch; url: concept-event-dispatch
@@ -4539,9 +4532,9 @@ apart from the timing model.
     :   <dfn argument for="AnimationEffect/updateTiming(timing)"
         lt="timing">optional {{OptionalEffectTiming}} timing</dfn>
     ::  The timing properties to update.
-        The timing properties corresponding to any members not <a>present</a>
-        on {{AnimationEffect/updateTiming(timing)/timing}} will <em>not</em>
-        be modified.
+        The timing properties corresponding to any members that do not
+        <a for="map">exist</a> on {{AnimationEffect/updateTiming(timing)/timing}} will
+        <em>not</em> be modified.
 
     </div>
 
@@ -4557,7 +4550,7 @@ The {{EffectTiming}} dictionary represents the timing properties of an
 {{AnimationEffect}}.
 
 The {{OptionalEffectTiming}} dictionary is a variant of the {{EffectTiming}}
-dictionary that allows some members to be not <a>present</a>.
+dictionary that allows some members to not <a for="map">exist</a>.
 This is used by the {{AnimationEffect/updateTiming()}} method of the
 {{AnimationEffect}} interface to perform a delta update to the timing properties
 of an [=animation effect=].