[docs-logs] Use struct in the complex type logging demo (open-telemetry#5577)

Co-authored-by: Cijo Thomas <cijo.thomas@gmail.com>

Author: reyang

docs/logs/complex-objects/FoodRecallNotice.cs

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-public class FoodRecallNotice
+public struct FoodRecallNotice
 {
     public string? BrandName { get; set; }
 

docs/logs/complex-objects/Program.cs

@@ -34,5 +34,5 @@ internal static partial class LoggerExtensions
     [LoggerMessage(LogLevel.Critical)]
     public static partial void FoodRecallNotice(
         this ILogger logger,
-        [LogProperties(OmitReferenceName = true)] FoodRecallNotice foodRecallNotice);
+        [LogProperties(OmitReferenceName = true)] in FoodRecallNotice foodRecallNotice);
 }

docs/logs/complex-objects/README.md

@@ -30,16 +30,12 @@ dotnet add package Microsoft.Extensions.Telemetry.Abstractions
 Define a new complex data type, as shown in [FoodRecallNotice.cs](./FoodRecallNotice.cs):
 
 ```csharp
-public class FoodRecallNotice
+public struct FoodRecallNotice
 {
     public string? BrandName { get; set; }
-
     public string? ProductDescription { get; set; }
-
     public string? ProductType { get; set; }
-
     public string? RecallReasonDescription { get; set; }
-
     public string? CompanyName { get; set; }
 }
 ```
@@ -54,7 +50,7 @@ internal static partial class LoggerExtensions
     [LoggerMessage(LogLevel.Critical)]
     public static partial void FoodRecallNotice(
         this ILogger logger,
-        [LogProperties(OmitReferenceName = true)] FoodRecallNotice foodRecallNotice);
+        [LogProperties(OmitReferenceName = true)] in FoodRecallNotice foodRecallNotice);
 }
 ```
 

docs/logs/complex-objects/complex-objects.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <SuppressTfmSupportBuildWarnings>true</SuppressTfmSupportBuildWarnings>
+    <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Telemetry.Abstractions" />