erc: Rename abnormal hooks to use "-functions" suffix (bug 34657)

* lisp/erc/erc.el (erc-before-connect, erc-after-connect):
Now obsolete aliases.  All uses changed.
(erc-before-connect-functions, erc-after-connect-functions):
New names with the standard suffix for abnormal hooks.

* etc/NEWS: Mention the changes.
2 jobs for fix/bug-34657-erc-hooks in 58 minutes and 12 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Test
passed #911
test-all

00:58:12

passed #912
test-filenotify-gio

00:44:47