Clarified choice of types in Java/C# codegen.

Change-Id: I1f094f350145d13b12cbe367bae7c623cfbbd8d3

src/idl_gen_general.cpp

@@ -252,6 +252,8 @@ static Type DestinationType(const LanguageParameters &lang, const Type &type,
                             bool vectorelem) {
   if (lang.language != GeneratorOptions::kJava) return type;
   switch (type.base_type) {
+    // We use int for both uchar/ushort, since that generally means less casting
+    // than using short for uchar.
     case BASE_TYPE_UCHAR:  return Type(BASE_TYPE_INT);
     case BASE_TYPE_USHORT: return Type(BASE_TYPE_INT);
     case BASE_TYPE_UINT:   return Type(BASE_TYPE_LONG);