Updated Sieve extension status in comments.

src/lib-sieve/plugins/editheader/ext-editheader.c

src/lib-sieve/plugins/environment/ext-environment.c

src/lib-sieve/plugins/ihave/ext-ihave.c

src/lib-sieve/plugins/include/ext-include.c

src/lib-sieve/plugins/mailbox/ext-mailbox.c

src/lib-sieve/plugins/spamvirustest/ext-spamvirustest.c

src/lib-sieve/plugins/vacation/ext-vacation-seconds.c

src/lib-sieve/plugins/vnd.dovecot/debug/ext-debug.c

src/lib-sieve/plugins/vnd.dovecot/duplicate/ext-duplicate.c

src/plugins/sieve-extprograms/ext-execute.c

src/plugins/sieve-extprograms/ext-filter.c

src/plugins/sieve-extprograms/ext-pipe.c