show: tweak warning message

'.' is "working directory parent" not "working directory."

hgext/show.py

@@ -182,7 +182,7 b' def showstack(ui, repo, displayer):'
                             'working directory'))
 
     if wdirctx.phase() == phases.public:
-        ui.write(_('(empty stack; working directory is a published '
+        ui.write(_('(empty stack; working directory parent is a published '
                    'changeset)\n'))
         return
 

tests/test-show-stack.t

@@ -77,7 +77,7 b' working dir on public changeset should d'
 
   $ hg -q up 1
   $ hg show stack
-  (empty stack; working directory is a published changeset)
+  (empty stack; working directory parent is a published changeset)
 
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