Move namespace sorter to alphasort module

To make room for an upcoming topological sorter in a toposort module.
diff --git a/gen/src/namespace_organizer.rs b/gen/src/alphasort.rs
similarity index 100%
rename from gen/src/namespace_organizer.rs
rename to gen/src/alphasort.rs
diff --git a/gen/src/mod.rs b/gen/src/mod.rs
index 453f47b..2cd4e56 100644
--- a/gen/src/mod.rs
+++ b/gen/src/mod.rs
@@ -1,6 +1,7 @@
 // Functionality that is shared between the cxx_build::bridge entry point and
 // the cxxbridge CLI command.
 
+mod alphasort;
 mod builtin;
 mod check;
 pub(super) mod error;
@@ -8,7 +9,6 @@
 pub(super) mod fs;
 mod ifndef;
 pub(super) mod include;
-mod namespace_organizer;
 pub(super) mod out;
 mod write;
 
diff --git a/gen/src/write.rs b/gen/src/write.rs
index 9f57f7d..e857d21 100644
--- a/gen/src/write.rs
+++ b/gen/src/write.rs
@@ -1,4 +1,4 @@
-use crate::gen::namespace_organizer::NamespaceEntries;
+use crate::gen::alphasort::NamespaceEntries;
 use crate::gen::out::OutFile;
 use crate::gen::{builtin, include, Opt};
 use crate::syntax::atom::Atom::{self, *};