✨ Parse all CONDSTORE response codes (RFC7162)

* `NOMODSEQ` _(already previously supported)_
* `HIGHESTMODSEQ`
* `MODIFIED`

Author: nevans

lib/net/imap/response_data.rb

@@ -292,6 +292,16 @@ class ResponseText < Struct.new(:code, :text)
     #   because the server doesn't allow deletion of mailboxes with children.
     #   #data is +nil+.
     #
+    # ==== +CONDSTORE+ extension
+    # See {[RFC7162]}[https://www.rfc-editor.org/rfc/rfc7162.html].
+    # * +NOMODSEQ+, when selecting a mailbox that does not support
+    #   mod-sequences.  #data is +nil+.  See IMAP#select.
+    # * +HIGHESTMODSEQ+, #data is an Integer, the highest mod-sequence value of
+    #   all messages in the mailbox.  See IMAP#select.
+    # * +MODIFIED+, #data is a SequenceSet, the messages that have been modified
+    #   since the +UNCHANGEDSINCE+ mod-sequence given to +STORE+ or <tt>UID
+    #   STORE</tt>.
+    #
     # ==== +OBJECTID+ extension
     # See {[RFC8474]}[https://www.rfc-editor.org/rfc/rfc8474.html].
     # * +MAILBOXID+, #data is a string

lib/net/imap/response_parser.rb

@@ -1802,6 +1802,8 @@ def resp_text
       #   resp-text-code   =/ "HIGHESTMODSEQ" SP mod-sequence-value /
       #                       "NOMODSEQ" /
       #                       "MODIFIED" SP sequence-set
+      # RFC7162 (QRESYNC):
+      #   resp-text-code   =/ "CLOSED"
       #
       # RFC8474: OBJECTID
       #   resp-text-code   =/ "MAILBOXID" SP "(" objectid ")"
@@ -1823,7 +1825,9 @@ def resp_text_code
             "EXPUNGEISSUED", "CORRUPTION", "SERVERBUG", "CLIENTBUG", "CANNOT",
             "LIMIT", "OVERQUOTA", "ALREADYEXISTS", "NONEXISTENT", "CLOSED",
             "NOTSAVED", "UIDNOTSTICKY", "UNKNOWN-CTE", "HASCHILDREN"
-          when "NOMODSEQ"           # CONDSTORE
+          when "NOMODSEQ"           then nil                       # CONDSTORE
+          when "HIGHESTMODSEQ"      then SP!; mod_sequence_value   # CONDSTORE
+          when "MODIFIED"           then SP!; sequence_set         # CONDSTORE
           when "MAILBOXID"          then SP!; parens__objectid     # RFC8474: OBJECTID
           else
             SP? and text_chars_except_rbra