refactor(@angular/build): add helper types to internal HTML rewriter

The `StartTag` and `EndTag` types are now also exported along with the
`htmlRewritingStream` factory. These types are commonly used with the
rewriter and by exporting them reduces the need to manually extract them
from the underlying methods.

Author: clydin

packages/angular/build/src/utils/index-file/html-rewriting-stream.ts

@@ -8,10 +8,16 @@
 
 import { Readable } from 'node:stream';
 import { pipeline } from 'node:stream/promises';
+import type { RewritingStream } from 'parse5-html-rewriting-stream';
 import { loadEsmModule } from '../load-esm';
 
+// Export helper types for the rewriter
+export type StartTag = Parameters<RewritingStream['emitStartTag']>[0];
+export type EndTag = Parameters<RewritingStream['emitEndTag']>[0];
+export type { RewritingStream };
+
 export async function htmlRewritingStream(content: string): Promise<{
-  rewriter: import('parse5-html-rewriting-stream').RewritingStream;
+  rewriter: RewritingStream;
   transformedContent: () => Promise<string>;
 }> {
   const { RewritingStream } = await loadEsmModule<typeof import('parse5-html-rewriting-stream')>(