Env: menu option for toggling all attenuverter sensitivities.

Env already supported low-sensitivity attenuverters but did
not have a way to toggle all of them in tandem.
Added the right-click menu option for doing that.

Also mentioned in the documentation that the attenuverters
have a low-sensitivity mode. Link to the dedicated doc for that topic.

Env.md

@@ -36,3 +36,7 @@ The V/OCT output reports the pitch of any detected signal. The zero volt level i
 a C4 note (261.625 Hz). Each unit volt indicates an octave. If no pitch can be detected,
 this port may output −10 V as a placeholder. Like the ENV port, V/OCT is polyphonic;
 there will be one channel of output for each channel of input on the AUDIO port.
+
+## Attenuverters
+
+Env supports [low-sensitivity attenuverters](LowSensitivityAttenuverterKnobs.md).

src/env_vcv.cpp

@@ -138,6 +138,15 @@ namespace Sapphire
                 addSapphireFlatControlGroup("frequency", FREQ_PARAM, FREQ_ATTEN, FREQ_CV_INPUT);
                 addSapphireFlatControlGroup("resonance", RES_PARAM, RES_ATTEN, RES_CV_INPUT);
             }
+
+            void appendContextMenu(Menu* menu) override
+            {
+                if (envModule == nullptr)
+                    return;
+
+                menu->addChild(new MenuSeparator);
+                menu->addChild(envModule->createToggleAllSensitivityMenuItem());
+            }
         };
     }
 }