Quoting the man page of vsnprintf:
RETURN VALUE
Upon successful return, these functions return the number of characters printed
(excluding the null byte used to end output to strings).
The functions snprintf() and vsnprintf() do not write more than size bytes (including
the terminating null byte ('\0')). If the output was truncated due to this limit,
then the return value is the number of characters (excluding the terminating null
byte) which would have been written to the final string if enough space had been
available. Thus, a return value of size or more means that the output was truncated.
(See also below under NOTES.)
If an output error is encountered, a negative value is returned.
[...]
The glibc implementation of the functions snprintf() and vsnprintf() conforms to the
C99 standard, that is, behaves as described above, since glibc version 2.1. Until
glibc 2.0.6, they would return -1 when the output was truncated.
This makes `LATIN SMALL LETTER L` confusable with `LATIN SMALL LETTER I`
because `CYRILLIC SMALL LETTER PALOCHKA` "ӏ" (mapping to i) wasn't
confusable with `LATIN SMALL LETTER L` "l" (mapping to l) before.
Also add tests for `str_utf8_comp_confusable`.
`str_utf8_isspace` now returns true if the passed code point renders as
a space, instead of when not.
Add `str_utf8_trim_right`, use this function and
`str_utf8_skip_whitespaces` in the server.
Add tests for the three functions
This uses the Unicode confusable data together with judging how close
two strings are by using the Levenshtein distance.
Adds the commands `name_ban`, `name_unban` and `name_bans`. Kicks
players who join using a banned name and doesn't allow ingame players to
change their names to the banned ones.
