Fix doc string for FullHostName

Summary:
When I did D50961086 I got the docstring wrong

`FullClusterName` is the actual name of the cluster (like `atn1c01`) which can differ from TW cluster when set to global allocations.

Reviewed By: andreacampi

Differential Revision:
D66054238

Privacy Context Container: L1257087

fbshipit-source-id: dccd4c341922ab8407183e2baf59d0b57ee5f82a

shed/scuba_sample/src/builder.rs

@@ -291,7 +291,7 @@ pub enum ServerData {
     ModelName,
     /// Model id of the server
     ModelId,
-    /// Tupperware full cluster name
+    /// Device full cluster name (ie `atn1c01`)
     FullClusterName,
     /// Tier of the service
     Tier,