Fixed naming conflicts in heterogeneous-hello-world (#2114)

* Fixed naming conflicts in heterogeneous-hello-world

Added 3 new modifiers (`__unmangled`, `__exportDirectly`, `__externLib`)

`__unmangled`  causes mangleName() to return the normal name of the decl.

`__exportDirectly` changes parent decl name concatenation behavior to use
"::" instead of "." (for Name Hint) and emits the name hint when it exists,
otherwise it emits the mangled name.

`__externLib` stops Slang from emitting the corresponding struct.

Also made necessary changes to heterogeneous-hello-world so that this new
functionality is shown off.

* Undo unintentional formatting changes

Co-authored-by: Yong He <yonghe@outlook.com>

0 files changed, 0 insertions, 0 deletions