message: [golang] Perform keyword escaping after case conversion
  Change config.escape_keywords to AfterConvertingCase.
  It avoids unecessay escaping since the generated native
  structs have fields starting with a uppercase letter
  and Go's keywords start with lowercase letters.
diff: @@ -61,7 +61,7 @@ Namer::Config GoDefaultConfig() {
  /*variables=*/Case::kLowerCamel,
  /*variants=*/Case::kKeep,
  /*enum_variant_seperator=*/"", // I.e. Concatenate.
  - /*escape_keywords=*/Namer::Config::Escape::BeforeConvertingCase,
  + /*escape_keywords=*/Namer::Config::Escape::AfterConvertingCase,
  /*namespaces=*/Case::kKeep,
  /*namespace_seperator=*/"__",
  /*object_prefix=*/"",
  