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)_.
expect(Object.keys(styles)).toEqual([fontName]);
      expect(items[0]).toEqual({
        dir: "ltr",
        fontName,
        height: 18,
        str: "Issue 8276",
        transform: [18, 0, 0, 18, 441.81, 708.4499999999999],
        width: 77.49,
        hasEOL: false,
      });
      expect(styles[fontName]).toEqual({
        fontFamily: "serif",
        ascent: NaN,
        descent: NaN,
        vertical: false,
      });
      await loadingTask.destroy();
    });
    it("gets text content, with no extra spaces (issue 13226)", async function () {
      const loadingTask = getDocument(buildGetDocumentParams("issue13226.pdf"));
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      const { items } = await pdfPage.getTextContent();
      const text = mergeText(items);
      expect(text).toEqual(
        "Mitarbeiterinnen und Mitarbeiter arbeiten in über 100 Ländern engagiert im Dienste"
      );
      await loadingTask.destroy();
    });
    it("gets text content, with merged spaces (issue 13201)", async function () {