Add missing module level docs

src/argparse.rs

@@ -2,6 +2,7 @@
 //
 // based on Daniel Grunwald's https://github.com/dgrunwald/rust-cpython
 
+//! Python argument parsing
 
 use ffi;
 use python::Python;

src/buffer.rs

@@ -16,6 +16,7 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+//! `PyBuffer` implementation
 use std::os::raw;
 use std::{mem, slice, cell};
 use std::ffi::CStr;

src/class/mod.rs

@@ -1,5 +1,7 @@
 // Copyright (c) 2017-present PyO3 Project and Contributors
 
+//! Python object protocols
+
 #[macro_use] mod macros;
 
 pub mod async;

src/ffi2/mod.rs

@@ -1,3 +1,4 @@
+//! Rust FFI declarations for Python 2
 #![no_std]
 #![allow(non_camel_case_types, non_upper_case_globals, non_snake_case)]
 

src/ffi3/mod.rs

@@ -1,3 +1,4 @@
+//! Rust FFI declarations for Python 3
 #![allow(non_camel_case_types, non_snake_case, non_upper_case_globals)]
 #![cfg_attr(Py_LIMITED_API, allow(unused_imports))]
 

src/freelist.rs

@@ -1,4 +1,6 @@
 // Copyright (c) 2017-present PyO3 Project and Contributors
+
+//! Free allocation list
 use std;
 
 use ffi;

src/lib.rs

@@ -143,6 +143,7 @@ mod ffi2;
 #[cfg(Py_3)]
 mod ffi3;
 
+/// Rust FFI declarations for Python
 pub mod ffi {
     #[cfg(not(Py_3))]
     pub use ffi2::*;
@@ -164,6 +165,7 @@ pub use conversion::{FromPyObject, ToPyObject, IntoPyObject, IntoPyTuple};
 pub mod class;
 pub use class::*;
 
+/// Procedural macros
 pub mod py {
     pub use pyo3cls::*;
 

src/typeob.rs

@@ -1,5 +1,7 @@
 // Copyright (c) 2017-present PyO3 Project and Contributors
 
+//! Python type object information
+
 use std;
 use std::mem;
 use std::ffi::{CStr, CString};