openPicker() {
      if (!this.suggestionItems.length || this.disabled || this.readonly) {
        return;
      }
      this._forceOpen = true;
    }
Manually opens the suggestions popover, assuming suggestions are enabled. Items must be preloaded for it to open.
@public
@method
@name sap.ui.webc.main.Input#openPicker
@return {void}
@since 1.3.0