Use #' consistently for :safe predicates

Author: bbatsov

cider-eldoc.el

@@ -82,7 +82,7 @@ a \"& x more\" suffix. Otherwise, all the classes are displayed."
 So in (map inc ...) when the cursor is over inc its eldoc would be
 displayed.  When nil, always display eldoc for first symbol of the sexp."
   :type 'boolean
-  :safe 'booleanp
+  :safe #'booleanp
   :group 'cider
   :package-version '(cider . "0.13.0"))
 

cider-repl.el

@@ -1069,13 +1069,13 @@ If USE-CURRENT-INPUT is non-nil, use the current input."
 (defcustom cider-repl-history-size 500
   "The maximum number of items to keep in the REPL history."
   :type 'integer
-  :safe 'integerp
+  :safe #'integerp
   :group 'cider-repl)
 
 (defcustom cider-repl-history-file nil
   "File to save the persistent REPL history to."
   :type 'string
-  :safe 'stringp
+  :safe #'stringp
   :group 'cider-repl)
 
 (defun cider-repl--history-read-filename ()