Fix bug with precious entries in Gnus registry

* lisp/registry.el (registry-collect-prune-candidates): This `cdr' was
  an error: it meant that the last key in the precious list, would be
  considered a nil. Since the precious list only contains the symbol
  'mark by default, marks were never considered precious.
* doc/misc/gnus.texi (Store arbitrary data): Fix typo: "marks" should
  be "mark".

2 files changed, 2 insertions, 2 deletions

diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index db0534e8a68..7be888f3f26 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -26159,7 +26159,7 @@ Get the data under @code{key} for message @code{id}.
 If any extra entries are precious, their presence will make the
 registry keep the whole entry forever, even if there are no groups for
 the Message-ID and if the size limit of the registry is reached.  By
-default this is just @code{(marks)} so the custom registry marks are
+default this is just @code{(mark)} so the custom registry marks are
 precious.
 @end defvar
 
diff --git a/lisp/registry.el b/lisp/registry.el
index 95097a4f1b7..04f3e7b974c 100644
--- a/lisp/registry.el
+++ b/lisp/registry.el
@@ -358,7 +358,7 @@ return LIMIT such candidates.  If SORTFUNC is provided, sort
 entries first and return candidates from beginning of list."
   (let* ((precious (oref db precious))
          (precious-p (lambda (entry-key)
-                       (cdr (memq (car entry-key) precious))))
+                       (memq (car entry-key) precious)))
          (data (oref db data))
          (candidates (cl-loop for k being the hash-keys of data
                               using (hash-values v)