Hello!

Let me know if i should have opened this issue on the [pdfjs-dist](https://github.com/mozilla/pdfjs-dist) repo but I though here would fit.

I'm using pdfjs-dist and I'm in need of some more types to be exported. I have no idea how the types end up in the dist-repo but would love to open a PR if only someone could point me in the right direction 😃 Since I was using an older version of pdfjs-dist I realize the only type I need that's not in the type defs in the latest release are _PageViewport_ from _[display/display_utils](https://github.com/mozilla/pdf.js/blob/master/src/display/display_utils.js#L153)_.
new Error(
          "PageViewport: Invalid rotation, must be a multiple of 90 degrees."
        )
      );
    });
    it("gets annotations", async function () {
      const defaultPromise = page.getAnnotations().then(function (data) {
        expect(data.length).toEqual(4);
      });
      const anyPromise = page
        .getAnnotations({ intent: "any" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      const displayPromise = page
        .getAnnotations({ intent: "display" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      const printPromise = page
        .getAnnotations({ intent: "print" })
        .then(function (data) {
          expect(data.length).toEqual(4);
        });
      await Promise.all([
        defaultPromise,
        anyPromise,
        displayPromise,
        printPromise,
      ]);