Annotate exception message

Summary:
See https://www.internalfb.com/intern/staticdocs/thrift/docs/features/exception/#exception-message

A custom (human-readable) exception message may be specified in a field, by annotating it with `thrift.ExceptionMessage`.

This should allow the message to appear both in SR Scuba (under "Error Reason What") and McRouter Scuba.

Reviewed By: disylh

Differential Revision: D75648540

fbshipit-source-id: 4166bbdb139dc8819213af4ba9f1a0244ef61153

Author: Emanuele Altieri

third-party/mcrouter/src/mcrouter/lib/network/gen/Common.thrift

@@ -23,26 +23,32 @@ namespace cpp2 facebook.memcache.thrift
 namespace py3 facebook.memcache.thrift
 
 exception CarbonResultBusy {
+  @thrift.ExceptionMessage
   1: string message
 }
 
 exception CarbonResultRemoteError {
+  @thrift.ExceptionMessage
   1: string message
 }
 
 exception CarbonResultDeadlineExceeded {
+  @thrift.ExceptionMessage
   1: string message
 }
 
 exception CarbonResultShutdown {
+  @thrift.ExceptionMessage
   1: string message
 }
 
 exception CarbonResultTryAgain {
+  @thrift.ExceptionMessage
   1: string message
 }
 
 exception CarbonResultInvalidRequest {
+  @thrift.ExceptionMessage
   1: string message
 }