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)_.
"1. The first of these cases arises from the tragic handicap which has blighted the life of the Plaintiff, and from the response of the"
        )
      ).toEqual(true);
      expect(
        text.includes(
          "argued in this Court the appeal raises narrower, but important, issues which may be summarised as follows:-"
        )
      ).toEqual(true);
      await loadingTask.destroy();
    });
    it("gets text content, with merged spaces (issue 10900)", async function () {
      const loadingTask = getDocument(buildGetDocumentParams("issue10900.pdf"));
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      const { items } = await pdfPage.getTextContent();
      const text = mergeText(items);
      expect(
        text.includes(`3 3 3 3
851.5 854.9 839.3 837.5
633.6 727.8 789.9 796.2
1,485.1 1,582.7 1,629.2 1,633.7
114.2 121.7 125.3 130.7
13.0x 13.0x 13.0x 12.5x`)
      ).toEqual(true);
      await loadingTask.destroy();
    });
    it("gets text content, with spaces (issue 10640)", async function () {
      const loadingTask = getDocument(buildGetDocumentParams("issue10640.pdf"));
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);