Fix some formatting issues, mostly around comments and whitespace.

src/ir.rs

@@ -1,12 +1,12 @@
 //! The middle of the compiler: analysis, simplification, optimization.
-//! 
+//!
 //! For the moment, this module doesn't do much besides define an intermediate
 //! representation for NGR programs that is a little easier to work with then
 //! the structures we've built from the actual user syntax. For example, in the
 //! IR syntax, function calls are simplified so that all their arguments are
 //! either variables or constants, which can make reasoning about programs
 //! (and implicit temporary variables) quite a bit easier.
-//! 
+//!
 //! For the foreseeable future, this module will likely remain mostly empty
 //! besides definitions, as we'll likely want to focus on just processing /
 //! validating syntax, and then figuring out how to turn it into Cranelift