Updating storage.md for retention.size (#7942)

Signed-off-by: venkatbvc <chalapathirao@gmail.com>

docs/storage.md

@@ -64,7 +64,7 @@ Prometheus has several flags that allow configuring the local storage. The most
 
 * `--storage.tsdb.path`: This determines where Prometheus writes its database. Defaults to `data/`.
 * `--storage.tsdb.retention.time`: This determines when to remove old data. Defaults to `15d`. Overrides `storage.tsdb.retention` if this flag is set to anything other than default.
-* `--storage.tsdb.retention.size`: [EXPERIMENTAL] This determines the maximum number of bytes that storage blocks can use (note that this does not include the WAL size, which can be substantial). The oldest data will be removed first. Defaults to `0` or disabled. This flag is experimental and can be changed in future releases. Units supported: B, KB, MB, GB, TB, PB, EB. Ex: "512MB"
+* `--storage.tsdb.retention.size`: [EXPERIMENTAL] This determines the maximum number of bytes that storage blocks can use. The oldest data will be removed first. Defaults to `0` or disabled. This flag is experimental and can be changed in future releases. Units supported: B, KB, MB, GB, TB, PB, EB. Ex: "512MB"
 * `--storage.tsdb.retention`: This flag has been deprecated in favour of `storage.tsdb.retention.time`.
 * `--storage.tsdb.wal-compression`: This flag enables compression of the write-ahead log (WAL). Depending on your data, you can expect the WAL size to be halved with little extra cpu load. This flag was introduced in 2.11.0 and enabled by default in 2.20.0. Note that once enabled, downgrading Prometheus to a version below 2.11.0 will require deleting the WAL.