Add auto-completion for puppet key:

Provides auto-complete options for puppet key sub-command.

custom/plugins/puppet/_puppet

@@ -314,6 +314,20 @@ _instrumentation_probe_arguments=(
   '--terminus: TERMINUS The indirector terminus to use'
 )
 
+local -a _key_arguments
+_key_arguments=(
+  'destroy:Delete an object'
+  'find:Retrieve an object by name'
+  'info:Print the default terminus class for this face'
+  'save:API only: create or overwrite an object'
+  'search:Search for an object or retrieve multiple objects'
+  '--render-as:FORMAT The rendering format to use'
+  '--verbose:Whether to log verbosely'
+  '--debug:Whether to log debug information'
+  '--extra:HASH Extra arguments to pass to the indirection request'
+  '--terminus: TERMINUS The indirector terminus to use'
+)
+
 
 __task_list ()
 {
@@ -631,6 +645,23 @@ __puppet-instrumentation_probe ()
   esac
 }
 
+__puppet-key ()
+{
+  local curcontext="$curcontext" state line
+  typeset -A opt_args
+
+  _arguments -C \
+    ':command:->command' \
+    '*::options:->options'
+
+  case $state in
+    (command)
+      _describe -t commands "gem subcommand" _key_arguments
+      return
+    ;;
+  esac
+}
+
 
 
 local expl
@@ -745,6 +776,11 @@ case $state in
       (instrumentation_probe)
           __puppet-instrumentation_probe
       ;;
+
+      # Display sub-commands for puppet key.
+      (key)
+          __puppet-key
+      ;;
     esac
   ;;
 esac