Improve progress-reporter state to remove hard coded length (bug#80988)

Remove hard-coded state range, now a monotonically increasing
integer.

* lisp/subr.el (progress-reporter-update-functions): Update
docstring.
(progress-reporter-echo-area): Use
'progress-reporter--pulse-characters' length.
(progress-reporter-do-update): Increase 'state' by 1 each pass.
*
lisp/system-taskbar.el (system-taskbar--progress-reporter-update):
Make steps independent of 'progress-reporter-echo-area' steps.

lisp/subr.el

@@ -7114,8 +7114,7 @@ REPORTER is the result of a call to `make-progress-reporter'.
 STATE can be one of:
 - A float representing the percentage complete in the range 0.0-1.0
 for a numeric reporter.
-- An integer representing the index which cycles through the range 0-3
-for a pulsing reporter.
+- A monotonically increasing integer for a pulsing reporter.
 - The symbol `done' to indicate that the progress reporter is complete.")
 
 (defsubst progress-reporter-update (reporter &optional value suffix)
@@ -7130,7 +7129,7 @@ MIN-VALUE and MAX-VALUE.
 Optional argument SUFFIX is a string to be displayed after REPORTER's
 main message and progress text.  If REPORTER is a non-numerical
 reporter, then VALUE should be nil, or a string to use instead of
-SUFFIX.  SUFFIX is considered obsolete and may be removed in the future.
+SUFFIX.
 
 See `progress-reporter-update-functions' for the list of functions
 called on each update.
@@ -7241,8 +7240,9 @@ area is busy with something else."
            (message "%s" text)))
         ((pred integerp)
          (let ((message-log-max nil)
-               (pulse-char (aref progress-reporter--pulse-characters
-                                 state)))
+               (pulse-char
+                (aref progress-reporter--pulse-characters
+                      (mod state (length progress-reporter--pulse-characters)))))
            (message "%s %s" text pulse-char)))
         ('done
          (message "%sdone" text))))))
@@ -7294,7 +7294,7 @@ area is busy with something else."
            (if suffix
                (aset parameters 6 suffix)
              (setq suffix (or (aref parameters 6) "")))
-           (let ((index (mod (1+ (car reporter)) 4)))
+           (let ((index (1+ (car reporter))))
 	     (setcar reporter index)
              (run-hook-with-args 'progress-reporter-update-functions
                                  reporter

lisp/system-taskbar.el

@@ -282,7 +282,9 @@ REPORTER and STATE are the same as in
       ((pred floatp)
        (system-taskbar--progress state))
       ((pred integerp)
-       (system-taskbar--progress (/ (1+ state) 4.0)))
+       ;; This won't show 0.0 to indicate work in process until done.
+       (system-taskbar--progress
+        (/ (1+ (mod state 5)) 5.0)))
       ('done
        (system-taskbar--progress nil)))))