[ivette] fix documentation issues

ivette/src/dome/renderer/dnd.tsx

@@ -99,7 +99,8 @@ function freshId(): string {
   return '<dnd-crashed>';
 }
 
-interface DropZone extends DropHandler {
+/** Extended `DropZone` with an HTML element. */
+export interface DropZone extends DropHandler {
   node: HTMLElement;
 }
 

ivette/src/dome/renderer/dome.tsx

@@ -581,7 +581,7 @@ export function useUpdate(...events: Event<any>[]): void {
   });
 }
 
-interface PromiseHook<A> {
+export interface PromiseHook<A> {
   result: A | undefined;
   error: Error | undefined;
   loading: boolean;
@@ -614,7 +614,7 @@ export function usePromise<A>(job: Promise<A>): PromiseHook<A> {
 }
 
 /* Internal type alias */
-type Serialize<A> = (a: A) => string;
+export type Serialize<A> = (a: A) => string;
 
 /**
    Hook to add a cache system to a function, allowing to reuse previous results.