In the following spots a "MouseUp" eventName is being used, which does look inconsistent considering that the "Mouse Down"/"Mouse Enter"/"Mouse Exit" eventNames all have a space in them.
Is this inconsistency actually expected, or is it a simple typo? If the former, then a comment explaining *why* would be appropriate; otherwise we should just fix this :-)

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L806

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L945

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L1034

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L1168

/cc @calixteman 
this.container.className = this.containerClassName;
    
    
    const data = this.data;
    const width = data.rect[2] - data.rect[0];
    const height = data.rect[3] - data.rect[1];
    const svg = this.svgFactory.create(width, height);
    for (const inkList of data.inkLists) {
      
      
      
      
      let points = [];
      for (const coordinate of inkList) {
        const x = coordinate.x - data.rect[0];
        const y = data.rect[3] - coordinate.y;
        points.push(`${x},${y}`);
      }
      points = points.join(" ");
      const polyline = this.svgFactory.createElement(this.svgElementName);
      polyline.setAttribute("points", points);
      
      
      polyline.setAttribute("stroke-width", data.borderStyle.width || 1);
      polyline.setAttribute("stroke", "transparent");
      polyline.setAttribute("fill", "none");
      
      
      this._createPopup(polyline, data);
      svg.appendChild(polyline);