Unbreak more tests

* sly.el (sly-simple-completions): Ressurected.
Improved and regex-capable apropos

* sly.el (sly-apropos-symbol): New button type.
(sly-apropos-designator-string, sly-apropos-insert-symbol): New
function.
(sly-print-apropos): Rewritten. Uses more buttons.
(sly-insert-xrefs): Add `sly-location' property to area near xref
button.

* lib/lisp/swank-backend.lisp (make-cl-ppcre-matcher)
(make-plain-matcher): New functions.
(make-apropos-matcher): Redesigned.

* lib/lisp/swank.lisp (apropos-list-for-emacs): Rewrittern with
for new retval of APROPOS-SYMBOLS.
(briefly-describe-symbol-for-emacs): Designator is now a triplet.
(apropos-symbols): Rewrite. Returns a list of lists.