Some docs

xtask/src/ast_src.rs

@@ -1,3 +1,5 @@
+//! Defines input for code generation process.
+
 pub(crate) struct KindsSrc<'a> {
     pub(crate) punct: &'a [(&'a str, &'a str)],
     pub(crate) keywords: &'a [&'a str],

xtask/src/codegen/gen_assists_docs.rs

@@ -1,3 +1,5 @@
+//! Generates `assists.md` documentation.
+
 use std::{fs, path::Path};
 
 use crate::{

xtask/src/lib.rs

@@ -1,4 +1,6 @@
-//! FIXME: write short doc here
+//! Support library for `cargo xtask` command.
+//!
+//! See https://github.com/matklad/cargo-xtask/
 
 pub mod not_bash;
 pub mod install;

xtask/src/not_bash.rs

@@ -1,4 +1,5 @@
 //! A bad shell -- small cross platform module for writing glue code
+
 use std::{
     cell::RefCell,
     env,