Improve format string parsing.
Improve format string parsing.

minaevmike/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,andrejzverev/rspamd,AlexeySa/rspamd,minaevmike/rspamd,minaevmike/rspamd,minaevmike/rspamd,andrejzverev/rspamd,AlexeySa/rspamd,andrejzverev/rspamd,andrejzverev/rspamd,minaevmike/rspamd,minaevmike/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,andrejzverev/rspamd,minaevmike/rspamd,andrejzverev/rspamd,minaevmike/rspamd,AlexeySa/rspamd,AlexeySa/rspamd,andrejzverev/rspamd,andrejzverev/rspamd,minaevmike/rspamd