Deprecate Raft in-flight cache max_bytes and max_elements metrics

Mark the in-flight cache max_bytes and max_elements Raft metrics as
deprecated in 2026.07 in the metrics reference.

Author: jackwaudby

modules/ROOT/pages/monitoring/metrics/reference.adoc

@@ -450,9 +450,9 @@ label:deprecated[Deprecated in 5.15]
 |<prefix>.cluster.raft.tx_retries|label:deprecated[Deprecated in 2025.02] Transaction retries. (counter)
 |<prefix>.cluster.raft.is_leader|Is this server the leader? Track this for each rafted primary database in the cluster. It reports `0` if it is not the leader and `1` if it is the leader. The sum of all of these should always be `1`. However, there are transient periods in which the sum can be more than `1` because more than one member thinks it is the leader. Action may be needed if the metric shows `0` for more than 30 seconds. (gauge)
 |<prefix>.cluster.raft.in_flight_cache.total_bytes|In-flight cache total bytes. (gauge)
-|<prefix>.cluster.raft.in_flight_cache.max_bytes|In-flight cache max bytes. (gauge)
+|<prefix>.cluster.raft.in_flight_cache.max_bytes|label:deprecated[Deprecated in 2026.07] In-flight cache max bytes. (gauge)
 |<prefix>.cluster.raft.in_flight_cache.element_count|In-flight cache element count. (gauge)
-|<prefix>.cluster.raft.in_flight_cache.max_elements|In-flight cache maximum elements. (gauge)
+|<prefix>.cluster.raft.in_flight_cache.max_elements|label:deprecated[Deprecated in 2026.07] In-flight cache maximum elements. (gauge)
 |<prefix>.cluster.raft.in_flight_cache.hits|In-flight cache hits. (counter)
 |<prefix>.cluster.raft.in_flight_cache.misses|In-flight cache misses. (counter)
 |<prefix>.cluster.raft.raft_log_entry_prefetch_buffer.lag|Raft log entry prefetch buffer lag. The amount of entries that have been added to the Raft log but not applied to the store. (gauge)