Feat: Enable all valid priority values

Expand recognised priority values from A-C to current org-mode
standard of A-Z and 0-64. Futher work is required to use
`org-get-priority-function` and support custom priority values.

org-ql.el

@@ -1735,15 +1735,14 @@ priority B)."
     `(priority ',comparator ,letter)))
 
   :preambles
-  (;; NOTE: This only accepts A, B, or C.  I haven't seen
-   ;; other priorities in the wild, so this will do for now.
-   (`(,predicate-names)
+  ((`(,predicate-names)
     ;; Any priority cookie.
-    (list :regexp (rx-to-string `(seq bol (1+ "*") (1+ blank) (0+ nonl) "[#" (in "ABC") "]") t)))
    (`(,predicate-names ,(and (or ''= ''< ''> ''<= ''>=) comparator) ,letter)
     ;; Comparator and priority letter.
+    (list :regexp (rx-to-string `(seq bol (1+ "*") (1+ blank) (0+ nonl) "[#" (or (in "A-Z") (1+ (in "0-9"))) "]") t)))
     ;; NOTE: The double-quoted comparators.  See below.
-    (let* ((priority-letters '("A" "B" "C"))
+    (let* ((priority-letters (append (mapcar #'number-to-string (number-sequence 0 64))
+                                     (mapcar #'string (number-sequence ?A ?Z))))
            (index (-elem-index letter priority-letters))
            ;; NOTE: Higher priority == lower number.
            ;; NOTE: Because we need to support both preamble-based queries and