Add "source of module name" to ModuleDescriptor API

[Alan Bateman]

On 04/07/2019 07:40, Christian Stein wrote:
> :
>
>  Thank you for the clarification, Alan.
>
> Wondering why `isAutomatic()` is part of the API then. Its underlying
> value is also not declared by the author of the module, but rather
> determined at/by the runtime.
>
Automatic modules require special treatment so it's very important that 
the runtime or other programs using the ModuleDescriptor API know if the 
module is an automatic module or not. This isn't the same thing as 
knowing how the name was generated as most programs shouldn't care about 
that, e.g. modules generated at run-time will be named by whatever 
system generates them.

-Alan