PCFX - remap some buttons, add (bad) mnemonics for mode buttons

src/BizHawk.Client.Common/movie/bk2/Bk2MnemonicLookup.cs

@@ -444,6 +444,10 @@ namespace BizHawk.Client.Common
 				["IV"] = '4',
 				["V"] = '5',
 				["VI"] = '6',
+				["MODE 1: Set A"] = 'a',
+				["MODE 1: Set B"] = 'b',
+				["MODE 2: Set A"] = 'A',
+				["MODE 2: Set B"] = 'B'
 			},
 			["PCE"] = new Dictionary<string, char>
 			{

src/BizHawk.Emulation.Cores/Consoles/NEC/PCFX/Tst.cs

@@ -49,5 +49,15 @@ namespace BizHawk.Emulation.Cores.Consoles.NEC.PCFX
 		{
 			"pcfx.slstart", "pcfx.slend",
 		};
+
+		protected override IDictionary<string, string> ButtonNameOverrides { get; } = new Dictionary<string, string>
+		{
+			["UP ↑"] = "Up",
+			["DOWN ↓"] = "Down",
+			["LEFT ←"] = "Left",
+			["RIGHT →"] = "Right",
+			["SELECT"] = "Select",
+			["RUN"] = "Run"
+		};
 	}
 }