Document the new search --exclude=all option.
-.BR \-\-exclude=(true|false|flag)
+.BR \-\-exclude=(true|false|all|flag)
A message is called "excluded" if it matches at least one tag in
search.tag_exclude that does not appear explicitly in the search terms.
A message is called "excluded" if it matches at least one tag in
search.tag_exclude that does not appear explicitly in the search terms.
.BR true ,
prevents excluded messages from matching the search terms.
.BR true ,
prevents excluded messages from matching the search terms.
+.B all
+additionally prevents excluded messages from appearing in displayed
+results, in effect behaving as though the excluded messages do not exist.
+
.B false
allows excluded messages to match search terms and appear in displayed
results. Excluded messages are still marked in the relevant outputs.
.B false
allows excluded messages to match search terms and appear in displayed
results. Excluded messages are still marked in the relevant outputs.