Date/time prompt: Allow input of relative time in hours (e.g. +1h)

* lisp/org.el (org-read-date-analyze): Match relative hour specifier.

Fixes https://orgmode.org/list/C9A76EFA-1D76-4C5D-941D-AFA288A64CD0@icloud.com

lisp/org.el

@@ -13684,10 +13684,14 @@ user."
       (unless deltadef
 	(let ((now (decode-time)))
 	  (setq day (nth 3 now) month (nth 4 now) year (nth 5 now))))
-      (cond ((member deltaw '("d" "")) (setq day (+ day deltan)))
-	    ((equal deltaw "w") (setq day (+ day (* 7 deltan))))
-	    ((equal deltaw "m") (setq month (+ month deltan)))
-	    ((equal deltaw "y") (setq year (+ year deltan)))))
+      (cond ((member deltaw '("h" ""))
+             (when (boundp 'org-time-was-given)
+               (setq org-time-was-given t))
+             (setq hour (+ hour deltan)))
+            ((member deltaw '("d" "")) (setq day (+ day deltan)))
+            ((equal deltaw "w") (setq day (+ day (* 7 deltan))))
+            ((equal deltaw "m") (setq month (+ month deltan)))
+            ((equal deltaw "y") (setq year (+ year deltan)))))
      ((and wday (not (nth 3 tl)))
       ;; Weekday was given, but no day, so pick that day in the week
       ;; on or after the derived date.