backport tim's 2.44

  Make clear in the docstring that "std" applies to both size and alignment,
  not just to alignment.  Spotted by Guido.

not normally bothering with docstring cleanups, but in this case Tim _did_
note it as a bugfix candidate, so I'll be nice :)

Modules/structmodule.c

@@ -9,12 +9,12 @@ Functions to convert between Python values and C structs.\n\
 Python strings are used to hold the data representing the C struct\n\
 and also as format strings to describe the layout of data in the C struct.\n\
 \n\
-The optional first format char indicates byte ordering and alignment:\n\
- @: native w/native alignment(default)\n\
- =: native w/standard alignment\n\
- <: little-endian, std. alignment\n\
- >: big-endian, std. alignment\n\
- !: network, std (same as >)\n\
+The optional first format char indicates byte order, size and alignment:\n\
+ @: native order, size & alignment (default)\n\
+ =: native order, std. size & alignment\n\
+ <: little-endian, std. size & alignment\n\
+ >: big-endian, std. size & alignment\n\
+ !: same as >\n\
 \n\
 The remaining chars indicate types of args and must match exactly;\n\
 these can be preceded by a decimal repeat count:\n\