Add missing using statement; other misc

Author: steveharter

docs/fundamentals/runtime-libraries/snippets/System.Reflection.Emit/PersistedAssemblyBuilder/Overview/csharp/GenerateMetadataSnippets.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections;
+using System.Globalization;
 using System.IO;
 using System.Reflection;
 using System.Reflection.Emit;

docs/fundamentals/runtime-libraries/system-reflection-emit-persistedassemblybuilder.md

@@ -120,7 +120,7 @@ The following example shows how to create resources and attach it to the assembl
 
 :::code language="csharp" source="./snippets/System.Reflection.Emit/PersistedAssemblyBuilder/Overview/csharp/GenerateMetadataSnippets.cs" id="Snippet2":::
 
-The following example shows how to read resources from the assembly created above.
+The following example shows how to read resources from the created assembly.
 
 :::code language="csharp" source="./snippets/System.Reflection.Emit/PersistedAssemblyBuilder/Overview/csharp/GenerateMetadataSnippets.cs" id="Snippet3":::