compiler warning [-Wstringop-overflow=] when formatting compiled format strings with styled args

[moshelooks]

I was working on a PR to add color support for compiled format strings when I hit an issue with the existing code (master) that I'm not sure how to handle. https://github.com/moshelooks/fmt adds a test that illustrates this:

fmt::format(FMT_COMPILE("x{}"), fmt::styled("foo", fmt::text_style()));

Gives warning like:

include/fmt/base.h:1981:31: warning: writing 8 bytes into a region of size 7 [-Wstringop-overflow=]

Full make output (Fedora, g++ (GCC) 14.2.1 20240801 (Red Hat 14.2.1-1)): warnings.txt. Thank you!

[vitaut]

Same as #4133.