fix: instance documentation typo (#1469)

Author: AlBlanc

docs/resources/instance_volume.md

@@ -24,7 +24,7 @@ resource "scaleway_instance_volume" "server_volume" {
 The following arguments are supported:
 
 - `type` - (Required) The type of the volume. The possible values are: `b_ssd` (Block SSD), `l_ssd` (Local SSD).
-- `size_in_gb` - (Optional) The size of the volume. Only one of `size_in_gb`, `from_volume_id` and `from_volume_id` should be specified.
+- `size_in_gb` - (Optional) The size of the volume. Only one of `size_in_gb`, `from_volume_id` and `from_snapshot_id` should be specified.
 - `from_volume_id` - (Optional) If set, the new volume will be copied from this volume. Only one of `size_in_gb`, `from_volume_id` and `from_snapshot_id` should be specified.
 - ``from_snapshot_id`` - (Optional) If set, the new volume will be created from this snapshot. Only one of `size_in_gb`, `from_volume_id` and `from_snapshot_id` should be specified.
 - `name` - (Optional) The name of the volume. If not provided it will be randomly generated.