Sync #'alist-get with #'setf support with FSF
ChangeLog addition:
2023-06-22 Richard Hopkins xemacs@unbit.co.uk
* alist.el (put-alist):
* alist.el (del-alist):
* alist.el (set-alist):
* alist.el (remove-alist): Add optional TESTFN, defaulting to #'equal.
* alist.el (alist-get): Sync with FSF and add #'defsetf form.