Make the macros deterministic, using BTreeMap instead of HashMap (#662)

This fixes compile errors in non-cargo build systems, which rely on the
rustc crate hash being the same between two compiles.

HashMap order is nondeterministic due to SipHasher initialization, so
macro-generated code would change between compiles.

macros/src/actionlike.rs

@@ -1,7 +1,7 @@
 use crate::utils;
 use proc_macro2::{Span, TokenStream};
 use quote::quote;
-use std::collections::HashMap;
+use std::collections::BTreeMap;
 use syn::{Attribute, Data, DataEnum, DeriveInput, Error, Ident};
 
 // This approach and implementation is inspired by the `strum` crate,
@@ -81,8 +81,8 @@ fn generate_input_control_kind_body(
 fn parse_variant_controls(
     data: &DataEnum,
     default_control: &Ident,
-) -> syn::Result<HashMap<Ident, Ident>> {
-    let mut map = HashMap::<Ident, Ident>::new();
+) -> syn::Result<BTreeMap<Ident, Ident>> {
+    let mut map = BTreeMap::<Ident, Ident>::new();
     for variant in data.variants.iter() {
         for attr in variant
             .attrs