Summary

Every declaration can now name the file it is realized by, so a document can be navigated back to the code. #120

Added

file <path> on concept, type, event, readmodel, projection, slice, specification and the top-level trigger, naming the repository relative file the declaration is realized by. #120
PLAY0264 warns when a file path is absolute rather than repository relative.
file offered as a completion in the declaration bodies that accept it.
A file references page covering what the keyword means on each construct and the rules a path follows.

ScreenplaySyntaxWalker.VisitFileReference reaches every file a document names, whichever construct named it.
Syntax nodes grow by init-only property rather than by a trailing optional record parameter, which is a binary break. Set File with an object initializer or a with expression.

The syntax tree compatibility page said appending an optional record parameter keeps consumers working. It is source compatible and binary breaking, so the page now states the hazard and prescribes the init property.