📚 Document SEARCH command, list extensions

Author: nevans

lib/net/imap.rb

@@ -1122,9 +1122,14 @@ def uid_expunge(uid_set)
     #
     # ===== Search criteria
     #
-    # The following are some common search criteria;
-    # see [{IMAP4rev1 §6.4.4}[https://www.rfc-editor.org/rfc/rfc3501.html#section-6.4.4]]
-    # for a full list:
+    # For a full list of search criteria,
+    # see [{IMAP4rev1 §6.4.4}[https://www.rfc-editor.org/rfc/rfc3501.html#section-6.4.4]],
+    # or  [{IMAP4rev2 §6.4.4}[https://www.rfc-editor.org/rfc/rfc9051.html#section-6.4.4]],
+    # in addition to documentation for
+    # any [CAPABILITIES[https://www.iana.org/assignments/imap-capabilities/imap-capabilities.xhtml]]
+    # reported by #capability which may define additional search filters, e.g:
+    # +CONDSTORE+, +WITHIN+, +FILTERS+, <tt>SEARCH=FUZZY</tt>, +OBJECTID+, or
+    # +SAVEDATE+.  The following are some common search criteria:
     #
     # <message set>:: a set of message sequence numbers.  "<tt>,</tt>" indicates
     #                 an interval, "+:+" indicates a range.  For instance,