[Dwarf-discuss] Proposal: Add C++23 DW_AT_language_version code

[Victor Chernyakin]

This is a proposal to add a version code for the latest ISO C++ standard, C++23, 
to the informative table at https://dwarfstd.org/languages-v6.html. Its value should be 202302 [1].

[1] https://herbsutter.com/2023/02/13/c23-pandemic-edition-is-complete-trip-report-winter-iso-c-standards-meeting-issaquah-wa-usa/