dsda: option to show input history

src/BizHawk.Emulation.Cores/Computers/Doom/DSDA.ISettable.cs

@@ -159,6 +159,11 @@ namespace BizHawk.Emulation.Cores.Computers.Doom
 			[DefaultValue(false)]
 			public bool DsdaExHud { get; set; }
 			
+			[DisplayName("Display Commands")]
+			[Description("Shows input history on the screen. History size is 20, empty commands are excluded.")]
+			[DefaultValue(false)]
+			public bool DisplayCommands { get; set; }
+			
 			[DisplayName("Automap Totals")]
 			[Description("Shows counts for kills, items, and secrets on automap.")]
 			[DefaultValue(true)]

src/BizHawk.Emulation.Cores/Computers/Doom/DSDA.cs

@@ -100,6 +100,7 @@ namespace BizHawk.Emulation.Cores.Computers.Doom
 				+ $"map_coordinates {     (_settings.MapCoordinates       ? 1 : 0)}\n"
 				+ $"hudadd_secretarea {   (_settings.ReportSecrets        ? 1 : 0)}\n"
 				+ $"show_messages {       (_settings.ShowMessages         ? 1 : 0)}\n"
+				+ $"dsda_command_display {(_settings.DisplayCommands      ? 1 : 0)}\n"
 				+ $"render_wipescreen {   (_syncSettings.RenderWipescreen ? 1 : 0)}\n"
 				+ "render_stretchsky 0\n"
 				+ "render_doom_lightmaps 1\n"
@@ -107,6 +108,7 @@ namespace BizHawk.Emulation.Cores.Computers.Doom
 				+ "render_stretch_hud 0\n"
 				+ "uncapped_framerate 0\n"
 				+ "dsda_show_level_splits 0\n"
+				+ "dsda_command_history_size 20\n"
 			);
 
 			_elf = new WaterboxHost(new WaterboxOptions