Re: Update of pcase docs for the elisp manual

[Stefan Monnier]

> It's not easy to find an example for a usage of the let pattern that is
> not too complicated and can't be replaced trivially with other patterns,
> and does also make at least a bit of sense.

The original motivation of `let' was in order to add a "missing" binding
in some `or' branches.  E.g.:

   (pcase foo
     ((or `(key . ,val) (let val 5)) val))


-- Stefan