Fix display of doc_leader with background color

Author: tleonhardt

cmd2/cmd2.py

@@ -4069,7 +4069,7 @@ def do_help(self, args: argparse.Namespace) -> None:
 
             if self.doc_leader:
                 self.poutput()
-                self.poutput(self.doc_leader, style=Cmd2Style.HELP_LEADER)
+                self.poutput(Text(self.doc_leader, style=Cmd2Style.HELP_LEADER))
             self.poutput()
 
             # Print any categories first and then the default category.