https://boersengefluester.de/wp-content/uploads/assets/annuals/2019/578560.pdf

Configuration:
- PDF.js version: 2.7.570

Steps to reproduce the problem:
1. Load the linked PDF
2. On the second page, highlight the word "Mitarbeiterinnen" by double-clicking it

What is the expected behavior?
The word should be recognized as a single word and highlighted as such.

What went wrong?
Instead, it's recognized as 3 words: "Mit", "arbei", "terinnen"
![image](https://user-images.githubusercontent.com/5265630/114384414-f8fe2a80-9b8e-11eb-8843-5099425b0fad.png)

This happens for many words in this PDF.

Is there anything that can be changed in how I use pdfjs-dist to make it recognize this as a single word? Just looking at the PDF, I can't tell what would cause this behavior.

const capability = createPromiseCapability();
    let styleCache = Object.create(null);
    
    const canvas = this._document.createElement("canvas");
    canvas.height = canvas.width = DEFAULT_FONT_SIZE;
    if (
      typeof PDFJSDev === "undefined" ||
      PDFJSDev.test("MOZCENTRAL || GENERIC")
    ) {
      canvas.mozOpaque = true;
    }
    this._layoutTextCtx = canvas.getContext("2d", { alpha: false });
    if (this._textContent) {
      const textItems = this._textContent.items;
      const textStyles = this._textContent.styles;
      this._processItems(textItems, textStyles);
      capability.resolve();
    } else if (this._textContentStream) {
      const pump = () => {
        this._reader.read().then(({ value, done }) => {
          if (done) {
            capability.resolve();
            return;
          }