Highlight multiple symbols in single quotes in CL strings

* lisp/emacs-lisp/lisp-mode.el (lisp-cl-font-lock-keywords-2): When
multiple space-delimited symbols are single quoted together (e.g "`foo
bar'"), highlight them.  (Bug#59360)

lisp/emacs-lisp/lisp-mode.el

@@ -559,7 +559,9 @@ This will generate compile-time constants from BINDINGS."
          (,(concat "(" cl-errs-re "\\_>")
            (1 font-lock-warning-face))
          ;; Words inside ‘’ and `' tend to be symbol names.
-         (,(concat "[`‘]\\(" (rx lisp-mode-symbol) "\\)['’]")
+         (,(concat "[`‘]\\("
+                   (rx (* lisp-mode-symbol (+ space)) lisp-mode-symbol)
+                   "\\)['’]")
           (1 font-lock-constant-face prepend))
          ;; Uninterned symbols, e.g., (defpackage #:my-package ...)
          ;; must come before keywords below to have effect