Set prompt_manager.width to zero for each new document to prevent misaligned Out prompts

IPython/sphinxext/ipython_directive.py

@@ -707,6 +707,7 b' class IPythonDirective(Directive):'
         if not self.state.document.current_source in self.seen_docs:
             self.shell.IP.history_manager.reset()
             self.shell.IP.execution_count = 1
+            self.shell.IP.prompt_manager.width = 0
             self.seen_docs.add(self.state.document.current_source)
 
         # and attach to shell so we don't have to pass them around