Fixing bug

[#448679] Left to right

* Python/compile.c
  (com_dictmaker): Reordered evaluation of dictionaries to follow strict
  LTR evaluation.

* Lib/compiler/pycodegen.py
  (CodeGenerator.visitDict): Reordered evaluation of dictionaries to
  follow strict LTR evaluation.

* Doc/ref/ref5.tex
  Documented the general LTR evaluation order idea.

* Misc/NEWS
  Documented change in evaluation order of dictionaries.