Small IR docs, and then some learning about rustdoc.

src/lib.rs

@@ -61,18 +61,14 @@
 //! for evaluating all expressions. The [`eval`] module provides some
 //! utility support for this work.
 //! 
-/// The front-end of the compiler: lexing, parsing, validation
 pub mod syntax;
-/// The middle of the compiler: analysis, simplification, optimization
 pub mod ir;
-/// The backend of the compiler: transformation to Cranelift, runtime
 pub mod backend;
-/// Helpful functions for evaluating NGR programs
 pub mod eval;
 
-/// Implementation module for the high-level compiler
+/// Implementation module for the high-level compiler.
 mod compiler;
-/// Implementation module for the high-level REPL
+/// Implementation module for the high-level REPL.
 mod repl;
 
 pub use crate::compiler::Compiler;