Suppress Clang 16 warnings. Closes #766

[HolyBlackCat]

Description

What: Silence Clang 16's -Wunsafe-buffer-usage.
Why: That + -Werror causes build errors in the examples.

GitHub Issues

#766

[codecov]

Codecov Report

Merging #768 (9336c9b) into dev (ae7a135) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##              dev     #768   +/-   ##
=======================================
  Coverage   92.11%   92.11%           
=======================================
  Files           2        2           
  Lines        2169     2169           
=======================================
  Hits         1998     1998           
  Misses        171      171           

Impacted Files	Coverage Δ
doctest/parts/doctest_fwd.h	96.55% <ø> (ø)

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[onqtam]

if the warning suppression is not recognized by most clang versions it can be made conditional with ifdefs only for clang 16 and if it happens only in 1-2 places it can also be made locally there. Also seems that clang 16 is harder to add to the build matrix

[HolyBlackCat]

@onqtam I think I've fixed it.

But some unrelated CI jobs are stuck as 'queued' me. 🤔 (upd: the jobs ultimately failed, but the same thing happened in the other PR too, so I don't think I did that)