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)_.
return _checkCanLoad(false, filename, options);
      }
      afterEach(async function () {
        if (loadingTask && !loadingTask.destroyed) {
          await loadingTask.destroy();
        }
      });
      it("server disallows cors", async function () {
        await testCannotLoad("basicapi.pdf");
      });
      it("server allows cors without credentials, default withCredentials", async function () {
        await testCanLoad("basicapi.pdf?cors=withoutCredentials");
      });
      it("server allows cors without credentials, and withCredentials=false", async function () {
        await testCanLoad("basicapi.pdf?cors=withoutCredentials", {
          withCredentials: false,
        });
      });
      it("server allows cors without credentials, but withCredentials=true", async function () {
        await testCannotLoad("basicapi.pdf?cors=withoutCredentials", {
          withCredentials: true,
        });
      });
      it("server allows cors with credentials, and withCredentials=true", async function () {
        await testCanLoad("basicapi.pdf?cors=withCredentials", {
          withCredentials: true,
        });
      });
      it("server allows cors with credentials, and withCredentials=false", async function () {