util.format: Ensure metatable __tostring results are also sanitized

mod_smacks: Include reason for destroying session on hibernation timeout To aid in debugging

tools/generate_format_spec: Apply lua-format to silence luacheck

util.format: Fix some formats expecting positive numbers in Lua 5.2 Amazing how string.format behaves differently under each Lua version

util.format: Fix Lua 5.1 quirks thanks to ALL THE TESTS

util.format: ALL THE TESTS!!! The more tests I made, the more Lua 5.1 quirks I discovered. Tests generated using a tool plus some touch-up.

util.format: Also handle the %p format added in Lua 5.4

util.format: Ensure sanitation of strings passed to wrong format Ie. log("debug", "%d", "\1\2\3") should not result in garbage. Also optimizing for the common case of ASCII string passed to %s and early returns everywhere. Returning nil from a gsub callback keeps the original substring.

util.format: Escape invalid UTF-8 by passing trough serialization Should prevent invalid UTF-8 from making it into the logs, which can cause trouble with terminals or log viewers or other tools, such as when grep determines that log files are binary.

mod_mam: Avoid storing bounces for messages from the bare account (thanks Ge0rG) This should rule out error replies to PEP notifications, which come from the account bare JID, and would be reflected back to it if they can't be delivered for some reason, e.g. s2s problems.