Updating API doc from fluidsynth master

Author: API Doc Deploy

api/RecentChanges.html

@@ -91,7 +91,6 @@
 What's new in 2.4.0?</h1>
 <ul>
 <li>synth.device-id now has a default value of 16</li>
-<li>synth.gain now has a default value of 0.6</li>
 <li>Default values of reverb and chorus settings have been tuned</li>
 <li><a class="el" href="group__modulators.html#ga0e06062983f1b03c8c069185bda00f88" title="Get the transform type of a modulator.">fluid_mod_get_transform()</a> and <a class="el" href="group__modulators.html#ga56e9f604c9d6a6f0c940a45baaff99a7" title="Set the transform type of a modulator.">fluid_mod_set_transform()</a> for SoundFont 2.04 compliant modulators</li>
 </ul>

api/fluidsettings.xml

@@ -141,7 +141,7 @@ Developers:
         <setting>
             <name>gain</name>
             <type>num</type>
-            <def>0.6 (since version 2.4.0),<br />0.2 (2.3.x and older)</def>
+            <def>0.2</def>
             <min>0.0</min>
             <max>10.0</max>
             <realtime/>

api/settings_synth.html

@@ -310,7 +310,7 @@ <h1><a class="anchor" id="settings_synth_gain"></a>
 <dl class="section user"><dt>Type</dt><dd>Float (num)</dd></dl>
 <dl class="section user"><dt>Min - Max</dt><dd>0.0 - 10.0</dd></dl>
 <dl class="section user"><dt>Default</dt><dd> 
-<def>0.6 (since version 2.4.0),<br>0.2 (2.3.x and older)</def>
+<def>0.2</def>
 </dd></dl>
 <dl class="section user"><dt>Real-time</dt><dd>This setting can be changed during runtime of the synthesizer.</dd></dl>
 <p>