Fix export generation

Author: GearsDatapacks

compiler-core/src/javascript/import.rs

@@ -64,9 +64,15 @@ impl<'a> Imports<'a> {
                 break_(",", " ")
             ]
             .group();
+
+            let export_keyword = match codegen_target {
+                JavaScriptCodegenTarget::JavaScript => "export {",
+                JavaScriptCodegenTarget::TypeScriptDeclarations => "export type {",
+            };
+
             imports
                 .append(line())
-                .append("export type {")
+                .append(export_keyword)
                 .append(names)
                 .append("};")
                 .append(line())

compiler-core/src/javascript/tests/snapshots/gleam_core__javascript__tests__type_alias__private_type_in_opaque_type.snap

@@ -1,8 +1,6 @@
 ---
 source: compiler-core/src/javascript/tests/type_alias.rs
-assertion_line: 14
 expression: "\ntype PrivateType {\n  PrivateType\n}\n\npub opaque type OpaqueType {\n  OpaqueType(PrivateType)\n}\n"
-snapshot_kind: text
 ---
 ----- SOURCE CODE
 
@@ -18,10 +16,6 @@ pub opaque type OpaqueType {
 ----- TYPESCRIPT DEFINITIONS
 import type * as _ from "../gleam.d.mts";
 
-declare class PrivateType extends _.CustomType {}
-
-declare type PrivateType$ = PrivateType;
-
 declare class OpaqueType extends _.CustomType {
   /** @deprecated */
   constructor(argument$0: PrivateType$);