Increase language server hackfmt timeout (facebook#112)

The `hh_client` language server launches a `hackfmt` subprocess
to implement the format command, with a hardcoded 2 seconds timeout.
This is too short to format some larger (~6k loc) Hack files,
so let's increase it a bit.

Author: mszabo-wikia

hphp/hack/src/client/ide_service/ide_format.ml

@@ -32,7 +32,8 @@ let call_external_formatter
     | _ -> Error "Call to hackfmt was killed"
   in
   Timeout.read_process
-    ~timeout:2
+    (* SLACK: bump timeout from 2s -> 6s to allow autoformatting large files *)
+    ~timeout:6
     ~on_timeout:(fun _ ->
       Hh_logger.log "Formatter timeout";
       Error "Call to hackfmt timed out")