Enable more analyzers and various code tweaks/cleanup (#738)

dotnet/samples/SemanticKernelMigration/OpenAI/Step03_DependencyInjection/Program.cs

@@ -13,10 +13,10 @@ var userInput = "Tell me a joke about a pirate.";
 
 Console.WriteLine($"User Input: {userInput}");
 
-await SKAgent();
-await AFAgent();
+await SKAgentAsync();
+await AFAgentAsync();
 
-async Task SKAgent()
+async Task SKAgentAsync()
 {
     Console.WriteLine("\n=== SK Agent ===\n");
 
@@ -36,7 +36,7 @@ async Task SKAgent()
     Console.WriteLine(result.Message);
 }
 
-async Task AFAgent()
+async Task AFAgentAsync()
 {
     Console.WriteLine("\n=== AF Agent ===\n");