nyma cores - fixes to mnemonic lookups and add a few overrides

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

@@ -450,10 +450,10 @@ 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'
+				["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/Waterbox/NymaCore.Controller.ButtonNameOverrides.cs

@@ -10,6 +10,12 @@ namespace BizHawk.Emulation.Cores.Waterbox
 		private static bool IsRomanNumeral(string str)
 			=> new[] {"I", "II", "III", "IV", "V", "VI"}.Contains(str);
 
+		private static readonly Dictionary<string, string> ButtonNameOverrides = new Dictionary<string, string>
+		{
+			["Left Shoulder"] = "L",
+			["Right Shoulder"] = "R"
+		};
+
 		/// <summary>
 		/// Override button names.  Technically this should be per core, but a lot of the names and overrides are the same,
 		/// and an override that doesn't apply to a particular core will just be ignored
@@ -23,6 +29,11 @@ namespace BizHawk.Emulation.Cores.Waterbox
 				original = CultureInfo.InvariantCulture.TextInfo.ToTitleCase(original.ToLowerInvariant());
 			}
 
+			if (ButtonNameOverrides.ContainsKey(original))
+			{
+				original = ButtonNameOverrides[original];
+			}
+
 			// TODO: Add dictionaries or whatever here as needed
 			return original;
 		}