* Migrate `sql/share/errmsg-utf8.txt` to use suffix-based, `-Wformat`
-compatible `my_snprintf` format extensions introduced in MDEV-21978
* Update relevant tests caught by BuildBot as well
While GCC `-Wformat` (with `ATTRIBUTE_FORMAT`) can catch obsolete or
malformed format string literals, formats originating from other sources
(such as this translations file) (still) require manual review.
This commit also escapes the only (1) instance of existing strings
conflicted by the introduction of suffixes:
(Not all `printf`s goes to `my_snprintf`, thus I `grep`ped and
confirmed that this does indeed land on `my_snprintf` eventually.)
chi "不能%sSLAVE'%.*s'"
This commit also fixes the following: (You’re welcome.)
* Delete extraneous spaces after the `%` (they’re all Swahili)
* Update `extra/comp_err.c`
* Add the missing standard C/C++ specifiers `c`, `i`, `o`, `p` and `X`
(Especially `%i`: it otherwise was complaining about the new `%iE`)
* Removed the old and obsolete extension formats `%b`, `%M` and `%T`