Enable search in buffer contents

[brunnerh]

When the list buffer command is invoked, the items can only be selected by index. It would be helpful if the contents could be searched as well, maybe only enabled via a configuration option.

(Searching contents can be enabled via the quick pick option matchOnDescription.)

[sirgru]

I also think this would be useful. The search would be in the same quick action dropdown that shows the buffer list.