Change: (--query-preamble) Use pcase for clarity

org-ql.el

@@ -261,8 +261,9 @@ a list of defined `org-ql' sorting methods: `date', `deadline',
 When QUERY has a clause with a corresponding preamble, and it's
 appropriate to use one (i.e. the clause is not in an `or'),
 replace the clause with a preamble."
-  (if org-ql-use-preamble
-      (let (org-ql-preamble)
+  (pcase org-ql-use-preamble
+    ('nil (list query nil))
+    (_ (let (org-ql-preamble)
          (cl-labels ((rec (element)
                           (or (when org-ql-preamble
                                 ;; Only one preamble is allowed
@@ -297,8 +298,7 @@ replace the clause with a preamble."
                               `((or)))
                           t)
                          (query (-flatten-n 1 query))))
-          (list query org-ql-preamble)))
-    (list query nil)))
+           (list query org-ql-preamble))))))
 
 (defun org-ql--select-cached (&rest args)
   "Return results for ARGS and current buffer using cache."