Add how to change input volume for pavucontrol-qt.

source/2/2.5/2.5.2/pulseaudio_volume_control.rst

@@ -9,6 +9,8 @@ The playback tab of pulseaudio volume control gives you the ability to the contr
 
 The output devices tab shows different output for different sounds. To mute one output such as a set of speakers presss the button that looks like a speaker with an X on it. To increase the volume of an output slide the slider for that output to the right. To decrease the volume for each output slide the slider to the left.
 
+To mute your microphone in pulseaudio toggle the button that looks like a speaker. To adjust input volume slide the slider to the right to increase volume or to the left to decrease volume. 
+
 Version
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 Lubuntu ships with version 0.4.0 Pulse Audio Volume Control.