fix tests

Author: soenneker

src/Soenneker.Gen.EnumValues/EnumValueSourceGenerator.Emission.cs

@@ -427,7 +427,7 @@ private static void AppendParsingMethods(StringBuilder source, in EnumSourceBuil
         source.AppendLine("    {");
         source.AppendLine("        if (name is null) { result = default!; return false; }");
         source.AppendLine();
-        source.AppendLine("        return TryFromName(name.AsSpan(), out result);");
+        source.AppendLine("        return TryFromName(global::System.MemoryExtensions.AsSpan(name), out result);");
         source.AppendLine();
         source.AppendLine("    }");
         source.AppendLine();