add instructions to configure "Quick launch" widget.

[bjlockie]

RMB click on lxpanel.
Select "Manage Widgets".
Select a "Quick launch" widget.
The gear to configure it is greyed out.
Maybe the bubble help could say to drag&drop applications on the widget to configure it.
Or the gear button could open a window saying to drag&drop.

System Information

LUbuntu-18.10

• Kernel: 4.18.0
  LXQt Version | 0.13.0
  Qt | 5.11.1

[sudogooglex]

It seems the configure option is not implemented yet.
https://github.com/lxqt/lxqt-panel/blob/master/plugin-quicklaunch/quicklaunchbutton.cpp

mMoveLeftAct = new QAction(XdgIcon::fromTheme("go-previous"), tr("Move left"), this);
connect(mMoveLeftAct, SIGNAL(triggered()), this, SIGNAL(movedLeft()));

mMoveRightAct = new QAction(XdgIcon::fromTheme("go-next"), tr("Move right"), this);
connect(mMoveRightAct, SIGNAL(triggered()), this, SIGNAL(movedRight()));


mDeleteAct = new QAction(XdgIcon::fromTheme("dialog-close"), tr("Remove from quicklaunch"), this);
connect(mDeleteAct, SIGNAL(triggered()), this, SLOT(selfRemove()));
addAction(mDeleteAct);
mMenu = new QMenu(this);
mMenu->addAction(mAct);
mMenu->addActions(mAct->addtitionalActions());
mMenu->addSeparator();
mMenu->addAction(mMoveLeftAct);
mMenu->addAction(mMoveRightAct);
mMenu->addSeparator();
mMenu->addAction(mDeleteAct);