Address #1857: Fix typos thru DelayNode (#1883)

* Fix typos
 * Remove a duplicate sentence.

index.bs

@@ -5960,7 +5960,7 @@ Attributes</h4>
 	: <dfn>type</dfn>
 	::
 		The type of this {{BiquadFilterNode}}. Its
-		default value is "lowpass". The exact meaning of the other
+		default value is "{{BiquadFilterType/lowpass}}". The exact meaning of the other
 		parameters depend on the value of the {{BiquadFilterNode/type}}
 		attribute.
 </dl>
@@ -5982,8 +5982,8 @@ Methods</h4>
 		processing block.
 
 		<pre class=argumentdef for="BiquadFilterNode/getFrequencyResponse()">
-			frequencyHz: This parameter specifies an array of frequencies at which the response values will be calculated.
-			magResponse: This parameter specifies an output array receiving the linear magnitude response values. If a value in the <code>frequencyHz</code> parameter is not within [0; sampleRate/2], where <code>sampleRate</code> is the value of the {{BaseAudioContext/sampleRate}} property of the {{AudioContext}}, the corresponding value at the same index of the <code>magResponse</code> array MUST be <code>NaN</code>.
+			frequencyHz: This parameter specifies an array of frequencies, in Hz, at which the response values will be calculated.
+			magResponse: This parameter specifies an output array receiving the linear magnitude response values. If a value in the <code>frequencyHz</code> parameter is not within [0, sampleRate/2], where <code>sampleRate</code> is the value of the {{BaseAudioContext/sampleRate}} property of the {{AudioContext}}, the corresponding value at the same index of the <code>magResponse</code> array MUST be <code>NaN</code>.
 			phaseResponse: This parameter specifies an output array receiving the phase response values in radians. If a value in the <code>frequencyHz</code> parameter is not within [0; sampleRate/2], where <code>sampleRate</code> is the value of the {{BaseAudioContext/sampleRate}} property of the {{AudioContext}}, the corresponding value at the same index of the <code>phaseResponse</code> array MUST be <code>NaN</code>.
 		</pre>
 
@@ -6591,9 +6591,6 @@ There are <a>channelCount constraints</a> and <a>channelCountMode
 constraints</a> for this node. These constraints ensure that the
 input to the node is either mono or stereo.
 
-{{ConvolverNode}}s are created with an internal flag <code>buffer
-set</code>, initially set to false.
-
 <pre class="idl">
 [Exposed=Window,
  Constructor (BaseAudioContext context, optional ConvolverOptions options)]