10846: fix: qualify struct name in struct constructor completion r=Veykril a=andrewleverette
* Alter `add_struct_literal` method signature to take an optional module path
* Update `render_literal` method to use a qualified
Relates to issue #10771
Side note: This is my first contribution. Any feedback is welcome!
Co-authored-by: Andrew Leverette <andrewleverette@gmail.com>