remove redundant space

index.bs

@@ -139,7 +139,7 @@ It represents the default audio session that is used by the user agent to automa
 The user agent will request or abandon audio focus when audio session [=audio session/elements=] start or finish playing.
 Upon creation of the {{Window}} object, its [=associated AudioSession=] MUST be set to a newly created {{AudioSession}} object with the {{Window}} object's [=relevant realm=].
 
-The [=associated AudioSession=] list of [=audio session/elements=] is updated dynamically as audio sources and sinks of the {{Window}} object  are created or removed.
+The [=associated AudioSession=] list of [=audio session/elements=] is updated dynamically as audio sources and sinks of the {{Window}} object are created or removed.
 
 <pre class="idl">
 [Exposed=Window]