message: [Kotlin] Fix missing escape for struct construction statements
  An escaping was missing leading to wrong generation when using
  kotlin keywords.
diff: @@ -425,7 +425,7 @@ class KotlinGenerator : public BaseGenerator {
  (nameprefix + (field.name + "_")).c_str());
  } else {
  writer.SetValue("type", GenMethod(field.value.type));
  - writer.SetValue("argname", nameprefix + MakeCamel(field.name, false));
  + writer.SetValue("argname", nameprefix + MakeCamel(Esc(field.name), false));
  writer.SetValue("cast", CastToSigned(field.value.type));
  writer += "builder.put{{type}}({{argname}}{{cast}})";
  }
  