bug#43502: 27.1; Gnus inconsistent keys for scoring on body?

[Allen Li]

The keys for making score entries against the body are:

    I b z ...

    Increase, score on body, substring

    I b p ...

    Increase, score on body, regexp

This is inconsistent with the keys for other entry types:

    I a s ...

    Increase, score on author, substring

    I a r ...

    Increase, score on author, regexp

This is also inconsistent with the manual (Gnus)Summary Score Commands,
which documents s/r for substring/regexp and not z/p

A side effect of this is that the shortcuts raise an error for body type
entries:

    I B should be equivalent to I b s(z?) t

But it errors, likely because s is not defined for I b

In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.22, cairo 
version 1.17.3)
 of 2020-08-28 built on juergen
Windowing system distributor 'The X.Org Foundation', version 11.0.12009000
System Description: Arch Linux