fix: allow for synchronous Hapi plugin register fn

types/hapi/index.d.ts

@@ -120,7 +120,7 @@ export interface PluginBase<T> {
      * * server - the server object with a plugin-specific server.realm.
      * * options - any options passed to the plugin during registration via server.register().
      */
-    register: (server: Server, options: T) => Promise<void>;
+    register: (server: Server, options: T) => void | Promise<void>;
 
     /** (optional) if true, allows the plugin to be registered multiple times with the same server. Defaults to false. */
     multiple?: boolean;

types/hapi/test/server/server-plugins.ts

@@ -13,6 +13,10 @@ interface Plugin3 {
 	three: 3;
 }
 
+interface Plugin4 {
+	four: 4;
+}
+
 declare module 'hapi' {
 	interface PluginProperties {
 		example: {
@@ -42,6 +46,11 @@ const plugin3: Plugin<Plugin3> = {
 	register: async (server: Server, options: Plugin3) => {}
 };
 
+const plugin4: Plugin<Plugin4> = {
+	name: 'plugin4',
+	register: (server: Server, options: Plugin4) => {}
+};
+
 const server = new Server({
     port: 8000,
 });
@@ -90,5 +99,9 @@ server.register([
 	{
 		plugin: plugin1,
 		options: {one: 1}
+	},
+	{
+		plugin: plugin4,
+		options: {four: 4}
 	}
 ]);