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)_.
passwordNeededCapability.resolve();
          updatePassword("qwerty"); 
          return;
        }
        if (
          reason === PasswordResponses.INCORRECT_PASSWORD &&
          !passwordIncorrectCapability.settled
        ) {
          passwordIncorrectCapability.resolve();
          updatePassword("asdfasdf"); 
          return;
        }
        
        expect(false).toEqual(true);
      };
      const data = await Promise.all([
        passwordNeededCapability.promise,
        passwordIncorrectCapability.promise,
        loadingTask.promise,
      ]);
      expect(data[2] instanceof PDFDocumentProxy).toEqual(true);
      await loadingTask.destroy();
    });
    it("creates pdf doc from PDF file protected with only a user password", async function () {
      const filename = "pr6531_2.pdf";
      const passwordNeededLoadingTask = getDocument(
        buildGetDocumentParams(filename, {
          password: "",
        })
      );