bug#23519: 25.0.93; pasting with the middle mouse button while searching doesn't work

[Stefan Monnier]

> This seems to have been caused due to this commit:
> http://git.savannah.gnu.org/cgit/emacs.git/commit/?h=emacs-25&id=0a21b26c58a241ac41cd12cd10cd605238bb2640

> Relevant portion from the diff:

> +    ;; Recognize the start of a bracketed paste sequence.  The handler
> +    ;; internally recognizes the end.
> +    (define-key map "\e[200~" [xterm-paste])

> Copying Stefan as he authored that commit.

In previous Emacsen, middle-button would be handled by the terminal
emulator which would end up sending the selection as if you had typed
those chars (so they'd sometimes be interpreted as key-combos).

Now we use a special mode in the terminal emulator which means the
terminal emulator actually tells us that it's a "paste" operation.

So the problem is that isearch currently doesn't have a binding for
xterm-paste.  We should add one, just like we added one to global-map.


        Stefan