Revert "nnimap.el: support additional expunge options"

This reverts commit 4e9baea6aba1633074889339dcc7cdc9d73880d3.

The patch broke fetching new mail:

Debugger entered--Lisp error: (error "Format specifier doesn’t match argument type")
  format("%d .*\n" (t ("OK" ("HIGHESTMODSEQ" "914696") "Expunge" "completed.") ("VANISHED" "1825937") ("0" "RECENT")))
  (looking-at (format "%d .*\n" sequence))
  (not (looking-at (format "%d .*\n" sequence)))
  (progn (while (and (not (bobp)) (progn (forward-line -1) (looking-at "\\*\\|[0-9]+ OK NOOP")))) (not (looking-at (format "%d .*\n" sequence))))

1 files changed, 3 insertions, 13 deletions

diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index e8524fb03f0..05159d4b2f7 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -14273,19 +14273,9 @@ specific login method to be used, you can set this variable to either
 @code{plain} or @code{cram-md5}.
 
 @item nnimap-expunge
-When to expunge deleted messages.  If @code{never}, deleted articles
-are marked with the IMAP @code{\\Delete} flag but not automatically
-expunged. If @code{immediately}, deleted articles are immediately expunged
-(this requires the server to support the UID EXPUNGE command). If
-@code{on-exit}, deleted articles are flagged, and all flagged articles are
-expunged when the group is closed.
-
-For backwards compatibility, this variable may also be set to t
-or nil. If the server supports UID EXPUNGE, both t and nil are
-equivalent to @code{immediately}. If the server does not support UID
-EXPUNGE nil is equivalent to @code{never}, while t will immediately
-expunge ALL articles that are currently flagged as deleted
-(i.e., potentially not only the article that was just deleted).
+If non-@code{nil}, expunge articles after deleting them.  This is always done
+if the server supports UID EXPUNGE, but it's not done by default on
+servers that doesn't support that command.
 
 @item nnimap-streaming
 Virtually all @acronym{IMAP} server support fast streaming of data.