Fix SF #1552093, eval docstring typo (3 ps in mapping)

Python/bltinmodule.c

@@ -607,7 +607,7 @@ PyDoc_STRVAR(eval_doc,
 Evaluate the source in the context of globals and locals.\n\
 The source may be a string representing a Python expression\n\
 or a code object as returned by compile().\n\
-The globals must be a dictionary and locals can be any mappping,\n\
+The globals must be a dictionary and locals can be any mapping,\n\
 defaulting to the current globals and locals.\n\
 If only globals is given, locals defaults to it.\n");