hrtimers: Update formatting of documentation

Documentation of functions lacks the annotations which are used by
kernel-doc and *.rst to make appearance in rendered documents more
user-friendly.

Use those annotations to improve user-friendliness. While at it prevent
duplication of comments and use a reference instead.

Signed-off-by: Anna-Maria Behnsen <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

include/linux/hrtimer.h

···
 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
 
 /**
- * hrtimer_forward_now - forward the timer expiry so it expires after now
+ * hrtimer_forward_now() - forward the timer expiry so it expires after now
  * @timer:	hrtimer to forward
  * @interval:	the interval to forward
  *
- * Forward the timer expiry so it will expire after the current time
- * of the hrtimer clock base. Returns the number of overruns.
- *
- * Can be safely called from the callback function of @timer. If
- * called from other contexts @timer must neither be enqueued nor
- * running the callback and the caller needs to take care of
- * serialization.
- *
- * Note: This only updates the timer expiry value and does not requeue
- * the timer.
+ * It is a variant of hrtimer_forward(). The timer will expire after the current
+ * time of the hrtimer clock base. See hrtimer_forward() for details.
  */
 static inline u64 hrtimer_forward_now(struct hrtimer *timer,
 				      ktime_t interval)

kernel/time/hrtimer.c

···
 }
 
 /**
- * hrtimer_forward - forward the timer expiry
+ * hrtimer_forward() - forward the timer expiry
  * @timer:	hrtimer to forward
  * @now:	forward past this time
  * @interval:	the interval to forward
  *
  * Forward the timer expiry so it will expire in the future.
- * Returns the number of overruns.
  *
- * Can be safely called from the callback function of @timer. If
- * called from other contexts @timer must neither be enqueued nor
- * running the callback and the caller needs to take care of
- * serialization.
+ * .. note::
+ *  This only updates the timer expiry value and does not requeue the timer.
  *
- * Note: This only updates the timer expiry value and does not requeue
- * the timer.
+ * There is also a variant of the function hrtimer_forward_now().
+ *
+ * Context: Can be safely called from the callback function of @timer. If called
+ *          from other contexts @timer must neither be enqueued nor running the
+ *          callback and the caller needs to take care of serialization.
+ *
+ * Return: The number of overruns are returned.
  */
 u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
 {