bug#30910: 26.0.91; Incorrect Edebug spec for def-edebug-spec

[Gemini Lasswell]

def-edebug-spec has an Edebug spec, which fails to match the valid
Edebug specs in lisp/emacs-lisp/cl-macs.el.

To reproduce, load cl-macs.el and:

M-x edebug-all-defs RET
M-x eval-buffer RET

Result: edebug-syntax-error: Invalid read syntax: "Expected one of",
"nil", edebug-spec-p, "t", "0", (&rest edebug-spec)

A simpler edebug spec than cl-lambda-list which also causes the error
is:

(def-edebug-spec buggy ((symbolp symbolp symbolp symbolp . [&or symbolp nil])))

Fewer than four symbolp's will not produce an error.