Explain sly-stickers a little bit more in NEWS.md
Avoid warnings from SLY's roll-your-own byte-compilation

SLY's hotspot compilation is a questionable but seductive idea. At
least make it not generate so much noise.

* sly.el (sly-byte-compile-hotspots): Renamed from
`sly--compile-hotspots'.

* contrib/sly-fontifying-fu.el: Use `sly-byte-compile-hotspots'

* lib/sly-parse.el: Use `sly-byte-compile-hotspots'
Erradicate compiler warnings

Actually leave one in contrib/sly-cl-indent.el that I have to analyse.

* sly.el: Replace functions from 'cl with their cl-lib
counterparts.
(require): Don't require 'cl, not even when compiling.
(sly-read-symbol-name): Move down to avoid compiler warning.
(sly-def-connection-var): Use gv-define-setter, not defsetf.
(sly--this-inspector-name): Move up to avoid compiler warning.

* contrib/sly-mrepl.el: Replace functions from 'cl with their cl-lib
counterparts.

* contrib/sly-stickers.el: Replace functions from 'cl with their cl-lib
counterparts.