ivy.el: More yank pulsing followups

[basil-conto]

(ivy-read): Ensure ivy--pulse-overlay is deleted before exiting completion.
(ivy--pulse-region): Add docstring. Only extend existing overlay's region if it is contiguous with the new region (re: #1856 (comment)).
(ivy--pulse-cleanup): Explicitly set ivy--pulse-timer and ivy--pulse-overlay to nil (re: #1856 (comment)).

Re: #1856
Cc: @mookid

[basil-conto]

@abo-abo Is there a more appropriate place to call ivy--pulse-cleanup in ivy-read?

[abo-abo]

Thanks.

Is there a more appropriate place to call ivy--pulse-cleanup in ivy-read?

Not sure, let's keep it as is for now.

I would also probably like to have a defcustom to turn the pulse off, with default value being on.

[basil-conto]

Thanks.

I would also probably like to have a defcustom to turn the pulse off, with default value being on.

At the moment I'm disabling the pulsing by setting ivy-pulse-delay to zero. Would you like to promote this variable to a user option or would you prefer a separate user option?

[abo-abo]

Would you like to promote this variable to a user option or would you prefer a separate user option?

I've promoted the variable to a defcustom, please have a look.

[basil-conto]

I've promoted the variable to a defcustom, please have a look.

Thanks, just a couple of comments (I'm AFK at the moment):

1. The docstring needs a second sentence such as "Nil means disable such highlighting."
2. The custom type should be number, not float.

[abo-abo]

@basil-conto Thanks