* test/lisp/cus-edit-tests.el (test-setopt):
Check for a warrning instead of an error in attempt to call `setopt`
with a value that does not match the declared type (bug#60162).
* doc/lispref/variables.texi (Setting Variables): Note type checking.
* lisp/cus-edit.el (setopt--set): New function to avoid having
Customize saving values, too.
(setopt): Use it.
* test/lisp/cus-edit-tests.el (cus-edit-tests-customize-saved/show-obsolete):
Add a fake saved-value property, to be able check that the obsolete
option is present in the Customize buffer. Expect the test to pass
now.