Bump stack number on autoreload fail to 10.

This would allow for easier to debug error when encountered.

IPython/extensions/autoreload.py

@@ -252,7 +252,7 b' class ModuleReloader(object):'
                         del self.failed[py_filename]
                 except:
                     print("[autoreload of %s failed: %s]" % (
-                            modname, traceback.format_exc(1)), file=sys.stderr)
+                            modname, traceback.format_exc(10)), file=sys.stderr)
                     self.failed[py_filename] = pymtime
 
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