RE: isearch multiple buffers

[Drew Adams]

> Using a dedicated mark requires creating a new keybinding and a new mark
> to be able to mark with a dedicated mark.  Wouldn't it be simple just have
> a dedicated key to start isearch on normal marks?

OK by me.

Another choice point: If there are marks in both Dired and Buffer List,
should the same key search all of them? Likewise, for marks in multiple
Dired buffers.

I think so, but there might be a reason to treat Dired marks and Buffer List
marks separately (?).

And if marks in multiple buffers are treated together (same key), and we
provide for a way to order the marks in a given buffer, what is the overall
order among the marks in the various Dired buffers and Buffer List?