‘make check-declare’ now chatters less

‘make check-declare’ now chatters less

* etc/NEWS: Document this.
* lisp/emacs-lisp/check-declare.el (check-declare-locate):
Return relative names, not absolute.
(check-declare-scan, check-declare-verify, check-declare-warn)
(check-declare-file, check-declare-directory):
Generate less chatter.  Use relative file names rather than
absolute.  Don’t give up on computing a good file name for a
diagnostic merely because the function name was bad.  Make
malformed declarations more noticeable.  Don’t warn about
"ext:..." declarations if check-declare-ext-errors is nil.
(check-declare-errmsg): Remove.
(check-declare-warn): New optional arg LINE.
(check-declare-files): Put status into mode line rather than
chattering.