fix: clarify partition labels

Author: pierreozoux

bare-metal/elastic-metal/how-to/configure-disk-partitions.mdx

@@ -163,7 +163,7 @@ Below is an example of how to define a partitioning schema with RAID and NVMe di
 
 - Disks:
     - Each disk is specified with its device path (e.g., `/dev/nvme0n1` or `/dev/nvme1n1`).
-    - Partitions are defined with labels like `swap`, `boot`, `root`, `data`, and an optional `uefi` partition for systems using UEFI.
+    - Partitions are defined with labels. Default value is `unknown_partition_label`, and possible values are: `uefi`, `legacy`, `root`, `boot`, `swap`, `data`, `home`, `raid`. Refer to [API documentation](https://www.scaleway.com/en/developers/api/elastic-metal/#path-servers-install-an-elastic-metal-server) if you have a doubt.
     - Each partition has a `number` and `size` in bytes.
 
 - RAID (Optional):
@@ -224,4 +224,4 @@ If you prefer a simpler configuration without RAID or ZFS, you can remove the `r
         "lvm": null
     }
 }
-```
+```