Simplify fix to use TestAttribute's CallerFilePath and CallerLineNumber

Improved the source location fix by leveraging the existing CallerFilePath
and CallerLineNumber parameters in TestAttribute constructor arguments,
which are automatically captured when the [Test] attribute is applied.

This approach is:
- Simpler and more reliable than parsing syntax trees
- Uses the built-in compiler-provided location information
- Removes the need for the GetMethodLocation helper method
- More consistent with how regular test methods get their source location

The TestAttribute already captures the exact file and line number via
[CallerFilePath] and [CallerLineNumber] attributes, making this the
preferred approach for getting accurate source locations.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

TUnit.Core.SourceGenerator/Generators/TestMetadataGenerator.cs

@@ -133,13 +133,13 @@ private static void GenerateInheritedTestSources(SourceProductionContext context
             // Calculate inheritance depth for this test
             int inheritanceDepth = CalculateInheritanceDepth(classInfo.TypeSymbol, method);
 
-            // Try to get the method's actual source location instead of the class location
-            var methodLocation = GetMethodLocation(method);
-            var filePath = methodLocation?.SourceTree?.FilePath ?? 
-                          testAttribute.ConstructorArguments.ElementAtOrDefault(0).Value?.ToString() ?? 
+            // Use the TestAttribute's CallerFilePath and CallerLineNumber for accurate source location
+            // These are automatically captured when the [Test] attribute is applied
+            var filePath = testAttribute.ConstructorArguments.ElementAtOrDefault(0).Value?.ToString() ?? 
                           classInfo.ClassSyntax.GetLocation().SourceTree?.FilePath ?? 
                           classInfo.ClassSyntax.SyntaxTree.FilePath;
-            var lineNumber = methodLocation?.GetLineSpan().StartLinePosition.Line + 1 ?? 
+
+            var lineNumber = (int?)testAttribute.ConstructorArguments.ElementAtOrDefault(1).Value ?? 
                             classInfo.ClassSyntax.GetLocation().GetLineSpan().StartLinePosition.Line + 1;
 
             var testMethodMetadata = new TestMethodMetadata
@@ -161,18 +161,6 @@ private static void GenerateInheritedTestSources(SourceProductionContext context
         }
     }
 
-    private static Location? GetMethodLocation(IMethodSymbol method)
-    {
-        // Try to get the method's original declaration location
-        var syntaxRef = method.DeclaringSyntaxReferences.FirstOrDefault();
-        if (syntaxRef != null)
-        {
-            var syntaxNode = syntaxRef.GetSyntax();
-            return syntaxNode.GetLocation();
-        }
-        return null;
-    }
-
     private static int CalculateInheritanceDepth(INamedTypeSymbol testClass, IMethodSymbol testMethod)
     {
         // If the method is declared directly in the test class, depth is 0