bug#31660: 26.1.50; EIEIO manual's Quick Start example makes Emacs unusable

[Gemini Lasswell]

The first example in the EIEIO manual defines a class called 'record'.
Evaluating this example changes the function definition of 'record',
which makes many Emacs commands produce errors, including find-file,
ielm, and report-emacs-bug.

To reproduce, with emacs -Q:

M-x info RET
Navigate to the Quick Start node in the EIEIO manual, and select
the (defclass record ...) example.
M-w
M-x ielm RET
(require 'eieio) RET
C-y RET

Result: *** IELM Error ***  Error during pretty-printing (bug in pp)

Definitely the name of the class in the examples in the manual should be
changed, so that the examples work.

Maybe it would also be a good idea for defclass to signal an error or
at least give a warning message if it is asked to define a class with
the same name as an existing function unless that function is from a
previous class definition.