Fix IDE0038 violations.

Author: SuuperW

.editorconfig

@@ -63,7 +63,7 @@ dotnet_diagnostic.IDE0032.severity = suggestion
 # Simplify default expression
 dotnet_diagnostic.IDE0034.severity = suggestion
 # Use pattern matching to avoid is check followed by a cast (without variable)
-dotnet_diagnostic.IDE0038.severity = warning
+dotnet_diagnostic.IDE0038.severity = warning # Note that this doesn't work with `dotnet build` but does work inside Visual Studio.
 # Use is null check
 dotnet_diagnostic.IDE0041.severity = warning
 # Deconstruct variable declaration

src/BizHawk.Client.Common/savestates/SavestateFile.cs

@@ -108,9 +108,9 @@ public void Create(string filename, SaveStateConfig config)
 					});
 			}
 
-			if (_movieSession.Movie.IsActive() && _movieSession.Movie is ITasMovie)
+			if (_movieSession.Movie.IsActive() && _movieSession.Movie is ITasMovie tasMovie)
 			{
-				bs.PutLump(BinaryStateLump.LagLog, tw => ((ITasMovie) _movieSession.Movie).LagLog.Save(tw));
+				bs.PutLump(BinaryStateLump.LagLog, tasMovie.LagLog.Save);
 			}
 		}
 
@@ -193,9 +193,9 @@ public bool Load(string path, IDialogParent dialogParent)
 				foreach (var (k, v) in bag) _userBag.Add(k, v);
 			}
 
-			if (_movieSession.Movie.IsActive() && _movieSession.Movie is ITasMovie)
+			if (_movieSession.Movie.IsActive() && _movieSession.Movie is ITasMovie tasMovie)
 			{
-				bl.GetLump(BinaryStateLump.LagLog, abort: false, tr => ((ITasMovie) _movieSession.Movie).LagLog.Load(tr));
+				bl.GetLump(BinaryStateLump.LagLog, abort: false, tasMovie.LagLog.Load);
 			}
 
 			return true;