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 
if (baseName.includes("mouse")) {
      
      element.addEventListener(baseName, event => {
        this.linkService.eventBus?.dispatch("dispatcheventinsandbox", {
          source: this,
          detail: {
            id: this.data.id,
            name: eventName,
            value: valueGetter(event),
            shift: event.shiftKey,
            modifier: this._getKeyModifier(event),
          },
        });
      });
    } else {
      
      element.addEventListener(baseName, event => {
        this.linkService.eventBus?.dispatch("dispatcheventinsandbox", {
          source: this,
          detail: {
            id: this.data.id,
            name: eventName,
            value: event.target.checked,
          },
        });
      });
    }
  }
  _setEventListeners(element, names, getter) {