doxygen: enable AUTOBRIEF, drop \brief

Especially for short descriptions, it is annoying to have to type \brief for
every single API doc.

Drop all \brief and enable the AUTOBRIEF feature of doxygen, which always takes
the first sentence of an API doc as the brief description.

Change-Id: I11a8a821b065a128108641a2a63fb5a2b1916e87
diff --git a/src/stat_item.c b/src/stat_item.c
index fcd6781..3b67ba0 100644
--- a/src/stat_item.c
+++ b/src/stat_item.c
@@ -42,7 +42,7 @@
 
 static void *tall_stat_item_ctx;
 
-/*! \brief Allocate a new group of counters according to description
+/*! Allocate a new group of counters according to description
  *  \param[in] ctx \ref talloc context
  *  \param[in] desc Statistics item group description
  *  \param[in] idx Index of new stat item group
@@ -114,7 +114,7 @@
 	return group;
 }
 
-/*! \brief Free the memory for the specified group of counters */
+/*! Free the memory for the specified group of counters */
 void osmo_stat_item_group_free(struct osmo_stat_item_group *grp)
 {
 	llist_del(&grp->list);
@@ -172,7 +172,7 @@
 	return idx_delta;
 }
 
-/*! \brief Skip all values of this item and update idx accordingly */
+/*! Skip all values of this item and update idx accordingly */
 int osmo_stat_item_discard(const struct osmo_stat_item *item, int32_t *idx)
 {
 	int discarded = item->values[item->last_offs].id + 1 - *idx;
@@ -181,7 +181,7 @@
 	return discarded;
 }
 
-/*! \brief Skip all values of all items and update idx accordingly */
+/*! Skip all values of all items and update idx accordingly */
 int osmo_stat_item_discard_all(int32_t *idx)
 {
 	int discarded = global_value_id + 1 - *idx;
@@ -190,7 +190,7 @@
 	return discarded;
 }
 
-/*! \brief Initialize the stat item module */
+/*! Initialize the stat item module */
 int osmo_stat_item_init(void *tall_ctx)
 {
 	tall_stat_item_ctx = tall_ctx;
@@ -198,7 +198,7 @@
 	return 0;
 }
 
-/*! \brief Search for item group based on group name and index */
+/*! Search for item group based on group name and index */
 struct osmo_stat_item_group *osmo_stat_item_get_group_by_name_idx(
 	const char *name, const unsigned int idx)
 {
@@ -215,7 +215,7 @@
 	return NULL;
 }
 
-/*! \brief Search for item group based on group name */
+/*! Search for item group based on group name */
 const struct osmo_stat_item *osmo_stat_item_get_by_name(
 	const struct osmo_stat_item_group *statg, const char *name)
 {