Accessibility: AutoDuck and Truncate silence effects.

Problem:
Screen readers don't automatically read the units of the values in text boxes.

Fix:
Add units the the accessibility name of the text boxes.

Thanks to Paul for providing ShuttleGui::NameSuffix(), which makes the code neat and readable.

src/effects/AutoDuck.cpp

@@ -441,6 +441,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                1, &mDuckAmountDb, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_DuckAmountDb, MAX_DuckAmountDb
             )
+            .NameSuffix(XO("db"))
             .AddTextBox(XO("Duck amount:"), wxT(""), 10);
          S.AddUnits(XO("dB"));
 
@@ -448,6 +449,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                2, &mMaximumPause, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_MaximumPause, MAX_MaximumPause
             )
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Maximum pause:"), wxT(""), 10);
          S.AddUnits(XO("seconds"));
 
@@ -455,6 +457,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                2, &mOuterFadeDownLen, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_OuterFadeDownLen, MAX_OuterFadeDownLen
             )
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Outer fade down length:"), wxT(""), 10);
          S.AddUnits(XO("seconds"));
 
@@ -462,6 +465,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                2, &mOuterFadeUpLen, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_OuterFadeUpLen, MAX_OuterFadeUpLen
             )
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Outer fade up length:"), wxT(""), 10);
          S.AddUnits(XO("seconds"));
 
@@ -469,6 +473,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                2, &mInnerFadeDownLen, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_InnerFadeDownLen, MAX_InnerFadeDownLen
             )
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Inner fade down length:"), wxT(""), 10);
          S.AddUnits(XO("seconds"));
 
@@ -476,6 +481,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                2, &mInnerFadeUpLen, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_InnerFadeUpLen, MAX_InnerFadeUpLen
             )
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Inner fade up length:"), wxT(""), 10);
          S.AddUnits(XO("seconds"));
       }
@@ -487,6 +493,7 @@ void EffectAutoDuck::PopulateOrExchange(ShuttleGui & S)
                2, &mThresholdDb, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_ThresholdDb, MAX_ThresholdDb
             )
+            .NameSuffix(XO("db"))
             .AddTextBox(XO("Threshold:"), wxT(""), 10);
          S.AddUnits(XO("dB"));
       }

src/effects/TruncSilence.cpp

@@ -767,6 +767,7 @@ void EffectTruncSilence::PopulateOrExchange(ShuttleGui & S)
                3, &mThresholdDB, NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_Threshold, MAX_Threshold
             )
+            .NameSuffix(XO("db"))
             .AddTextBox(XO("Threshold:"), wxT(""), 0);
          S.AddUnits(XO("dB"));
 
@@ -775,6 +776,7 @@ void EffectTruncSilence::PopulateOrExchange(ShuttleGui & S)
                3, &mInitialAllowedSilence,
                NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_Minimum, MAX_Minimum)
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Duration:"), wxT(""), 12);
          S.AddUnits(XO("seconds"));
       }
@@ -803,6 +805,7 @@ void EffectTruncSilence::PopulateOrExchange(ShuttleGui & S)
                NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_Truncate, MAX_Truncate
             )
+            .NameSuffix(XO("seconds"))
             .AddTextBox(XO("Truncate to:"), wxT(""), 12);
          S.AddUnits(XO("seconds"));
 
@@ -811,6 +814,7 @@ void EffectTruncSilence::PopulateOrExchange(ShuttleGui & S)
                NumValidatorStyle::NO_TRAILING_ZEROES,
                MIN_Compress, MAX_Compress
             )
+            .NameSuffix(XO("%"))
             .AddTextBox(XO("Compress to:"), wxT(""), 12);
          S.AddUnits(XO("%"));
       }