mq: add correct documentation for qpop

hgext/mq.py

@@ -1943,7 +1943,11 b' def push(ui, repo, patch=None, **opts):'
     return ret
 
 def pop(ui, repo, patch=None, **opts):
-    """pop the current patch off the stack"""
+    """pop the current patch off the stack
+    
+    By default, pops off the top of the patch stack. If given a patch name,
+    keeps popping off patches until the named patch is at the top of the stack.
+    """
     localupdate = True
     if opts['name']:
         q = queue(ui, repo.join(""), repo.join(opts['name']))