bug#64070: 29.0.91; (documentation) Errors when byte-compiling annotated Flymake example

[Graham Marlow]

Hello,

When following the annotated Flymake example to create my own backend, I
noticed that flymake itself reports an error with the
example. Specifically,

"Wrong type argument: proper-list-p, (beg . end)"

This error also occurs when attempting to batch-byte-compile the file:

$ emacs -batch -L . -f batch-byte-compile example.el

In toplevel form:
example.el:7:2: Error: Wrong type argument: proper-list-p, (beg . end)

It looks like the example is missing a (require 'cl-lib) statement. I
checked the master Emacs branch and the bug is still there
(doc/misc/flymake.texi).

https://www.gnu.org/software/emacs/manual/html_mono/flymake.html#An-annotated-example-backend