* etc/ERC-NEWS: New section for ERC 5.6.2 and new entry mentioning
slight change in `erc-channel-user' accessor behavior.
* lisp/erc/erc-common.el (erc-channel-user): Change type for status slot
to natnum from integer.
* lisp/erc/erc.el (erc-channel-user-signal-if-status-unknown): New
variable.
(erc--define-channel-user-status-compat-getter): Only use fallback in
Non-ERC buffers because "obviously" a status flag is unusable if the
server doesn't advertise it or, rather, advertises nonsupport via its
absence. This regression was introduced in ERC 5.6.
(erc-channel-begin-receiving-names): Sharp-quote function name.
(erc--get-prefix-flag): Mention in doc that a return value of nil can
also mean the status flag is not supported by the server.
* test/lisp/erc/erc-tests.el (erc--parsed-prefix): Show that it returns
nil in a non-ERC buffer.
(erc-tests--make-combinations)
(erc-tests--with-channel-user-status-accessors): New functions.
(erc-channel-user/status-accessors/solo/default)
(erc-channel-user/status-accessors/solo/ov)
(erc-channel-user/status-accessors/multi/default)
(erc-channel-user/status-accessors/multi/ov): New tests.
(Bug#67220)
