swift: Make initialization fns have a stable ordering (#2651)

Author: bendk

CHANGELOG.md

@@ -26,6 +26,8 @@
   Custom types too ([#2603](https://github.com/mozilla/uniffi-rs/pull/2603))
 - Kotlin: The `NoPointer` placeholder object used to create fake interface instances has been renamed to `NoHandle`
 - Python: methods now have typing annotations for return values ([#2625](https://github.com/mozilla/uniffi-rs/issues/2625))
+- Swift: initialization functions now have a stable ordering when using external types.
+  This makes the generated source files more deterministic.
 
 ### ⚠️ Breaking Changes for external bindings authors ⚠️
 

uniffi_bindgen/src/bindings/swift/gen_swift/mod.rs

@@ -506,8 +506,8 @@ impl<'a> SwiftWrapper<'a> {
                     module_path.to_upper_camel_case()
                 )
             })
-            // Collect into a hash set to de-dup
-            .collect::<HashSet<_>>();
+            // Collect into a btree set to de-dup and order
+            .collect::<BTreeSet<_>>();
 
         init_fns.chain(extern_module_init_fns).collect()
     }