* lisp/mail/rmailsum.el (rmail-summary-sender-function)
(rmail-summary-recipient-function, rmail-summary-address-width):
New user options.
(rmail-summary--address-display, rmail-summary-name-or-address)
(rmail-summary-recipient-strip-quoted-names)
(rmail-summary-recipient-names): New functions.
(rmail-header-summary): Use them when formatting sender and
recipient fields (bug#80406).
* doc/emacs/rmail.texi (Rmail Make Summary): Document them.
* test/lisp/mail/rmailsum-tests.el: New file.
(rmailsum-tests-name-or-address-prefers-name)
(rmailsum-tests-name-or-address-fallback-to-address)
(rmailsum-tests-recipient-strip-quoted-names-first-line)
(rmailsum-tests-recipient-names-folded)
(rmailsum-tests-recipient-names-fallback-to-address): New tests.
ab4be3cc1f