Editorial: add missing identation

Author: gabrielsanbrito

index.bs

@@ -2002,7 +2002,7 @@ Methods</h4>
                         {{BaseAudioContext/statechange}} at the {{AudioContext}}.
 
                 1. Reject the promise with {{InvalidStateError}}, abort these
-                steps, returning <var>promise</var>.
+                    steps, returning <var>promise</var>.
 
             1. If the context is not <a>allowed to start</a>, append
                 <var>promise</var> to {{BaseAudioContext/[[pending promises]]}}