no license information in json_fwd.hpp

[berberic2]

There is no license information in json_fwd.hpp

I wanted to add the single-file version and the forward-header to an (open-source) project and have been asked to add license-information into json_fwd.hpp.

Wouldn’t it be useful to add a single-line license-information to this file, to prevent confusion?

[nlohmann]

The MIT license not really requires adding the license to all files, but I may work on this in the future.