Add some utilities to `libsyntax` Adds a few functions to `Mark` and `Span` that I found useful in an upcoming refactor of NLL region error reporting. Also includes some new documentation based on my discussion with @jseyfried on IRC. r? @jseyfried
Add some utilities to `libsyntax` Adds a few functions to `Mark` and `Span` that I found useful in an upcoming refactor of NLL region error reporting. Also includes some new documentation based on my discussion with @jseyfried on IRC. r? @jseyfried