monster order rules

<Someone> wrote:
> From the mkclass() comments:
>
> /*      Assumption #2:  monsters of a given class are presented in ascending
> *                      order of strength.
> */
>
> And monst.c:
>
>  *      Rule #2:        monsters of a given class are presented in ascending
>  *                      order of strength.
>
>  *      Rule #4:        monster subclasses (e.g. giants) should be kept
>  *                      together, unless it violates Rule 2.  NOGEN monsters
>  *                      won't violate Rule 2.
>
> Inspecting my monster-difficulty spoiler, I see the following places
> that these precepts are violated: do they cause potential problems?
> (Insofar as occasionally incorrectly miscalculating the probabilities
> for monster generation is a "problem", that is...)
>
> SPECIES                DIF
> ~~~~~~~~~~~~~~~~~~~~~~ ~~~
> d                  dog   5
> d            large dog   7
> d                dingo   5
>
> d                 warg   8
> d      winter wolf cub   7
> d          winter wolf   9
>
> u        white unicorn   6
> u         gray unicorn   6
> u        black unicorn   6
> u                 pony   4
>
> H          frost giant  13
> H          storm giant  19
> H                ettin  13
>
> P        black pudding  12
> P          green slime   8
>
> S            pit viper   9
> S               python   8
> S                cobra  10
>
> Z         giant zombie   9
> Z                ghoul   5
>
> @                nurse  13
> @              soldier   8
> @             sergeant  10
>
> &         horned devil   9
> &             succubus   8
>
> &               balrog  20
> &            sandestin  15
>
> (I've just realised that these may have already been fixed, and
> waiting on a file-compatibility-breaking release; if so, ignore me :-)

doc/fixes35.0

@@ -136,4 +136,5 @@ move all flags that are system or port specific from flag struct to sysflags
 	struct which is used only if SYSFLAGS is defined
 all fields in flags struct are unconditionally present
 monst cham field now a short and uses mons[] index
+rearrange some monster ordering to follow rule #2 listed at top of monst.c