[web-animations-1] Fix a few more broken links

See w3c#8382.

Author: birtles

web-animations-1/Overview.bs

@@ -4742,30 +4742,32 @@ To <dfn>update the timing properties of an animation effect</dfn>, |effect|,
 from an {{EffectTiming}} or {{OptionalEffectTiming}} object, |input|, perform
 the following steps:
 
-1.  If the {{EffectTiming/iterationStart}} member of |input| is <a>present</a>
-    and less than zero, <a>throw</a> a <span
+1.  If the {{EffectTiming/iterationStart}} member of |input|
+    <a for=map>exists</a> and is less than zero, <a>throw</a> a <span
     class=exceptionname>TypeError</span> and abort this procedure.
 
     Note: The reason for using a <span class=exceptionname>TypeError</span>
     rather than a <span class=exceptionname>RangeError</span> is to mirror
     the behavior of WebIDL's <a>[EnforceRange]</a> annotation should that
     annotation be able to be used with floating-point values in the future.
 
-1.  If the {{EffectTiming/iterations}} member of |input| is <a>present</a>, and
-    less than zero or is the value <code class=esvalue>NaN</code>, <a>throw</a>
-    a <span class=exceptionname>TypeError</span> and abort this procedure.
+1.  If the {{EffectTiming/iterations}} member of |input| <a for=map>exists</a>,
+    and is less than zero or is the value <code class=esvalue>NaN</code>,
+    <a>throw</a> a <span class=exceptionname>TypeError</span>
+    and abort this procedure.
 
-1.  If the {{EffectTiming/duration}} member of |input| is <a>present</a>, and
-    less than zero or is the value <code class=esvalue>NaN</code>, <a>throw</a>
-    a <span class=exceptionname>TypeError</span> and abort this procedure.
+1.  If the {{EffectTiming/duration}} member of |input| <a for=map>exists</a>,
+    and is less than zero or is the value <code class=esvalue>NaN</code>,
+    <a>throw</a> a <span class=exceptionname>TypeError</span>
+    and abort this procedure.
 
-1.  If the {{EffectTiming/easing}} member of |input| is <a>present</a>
+1.  If the {{EffectTiming/easing}} member of |input| <a for=map>exists</a>
     but cannot be parsed using the <<easing-function>> production
     [[!CSS-EASING-1]], <a>throw</a> a <span class=exceptionname>TypeError</span>
     and abort this procedure.
 
-1.  Assign each member <a>present</a> in |input| to the corresponding timing
-    property of |effect| as follows:
+1.  Assign each member that <a for=map>exists</a> in |input| to the
+    corresponding timing property of |effect| as follows:
 
     *   {{EffectTiming/delay}} &rarr; [=start delay=]
     *   {{EffectTiming/endDelay}} &rarr; [=end delay=]