[scroll-animations-1] Editorial: 'a element' → 'an element'

Author: birtles

scroll-animations-1/Overview.bs

@@ -445,7 +445,7 @@ A <dfn>scroll timeline offset</dfn> is provided by authors and determines a
 There are two types of scroll timeline offset: [=container-based offset=], and
 [=element-based offset=]. To <dfn>resolve a scroll timeline offset</dfn> into an
 [=effective scroll offset=], run the procedure to [=resolve a container-based
-offset=] or to [=resolve a element-based offset=] depending on the offset type.
+offset=] or to [=resolve an element-based offset=] depending on the offset type.
 It is possible for a [=scroll timeline offset=] to be resolved to null.
 
 The <dfn>effective start offset</dfn> is the [=effective scroll offset=] that is
@@ -528,7 +528,7 @@ checked anywhere.
 </div>
 
 
-The procedure to <dfn>resolve a element-based offset</dfn> given
+The procedure to <dfn>resolve an element-based offset</dfn> given
 <var>offset</var> is as follows:
 
 1.  If {{source}} is null, does not currently have a [=CSS layout box=], or if