message: Clarify that FlatBuffers unions do not support scalars
  I mention that a common practice is to wrap the scalar value in a table
  or a struct.
diff: @@ -211,9 +211,11 @@ If you have a need to distinguish between different FlatBuffers in a more
  open-ended way, for example for use as files, see the file identification
  feature below.
  -There is an experimental support only in C++ for a vector of unions
  -(and types). In the example IDL file above, use [Any] to add a
  -vector of Any to Monster table.
  +There is an experimental support only in C++ for a vector of unions (and
  +types). In the example IDL file above, use [Any] to add a vector of Any to
  +Monster table. There is also experimental support for other types besides
  +tables in unions, in particular structs and strings. There's no direct support
  +for scalars in unions, but they can be wrapped in a struct at no space cost.
  ### Namespaces
  