LWG4156 error_category messages have unspecified encoding

[jwakely]

https://cplusplus.github.io/LWG/issue4156

LWG would like SG16 to look at this issue please (and please note the comment about a comprehensive paper).

[vitaut]

Should be resolved by the following paper just approved by SG16: https://isocpp.org/files/papers/P3395R1.html.

[jwakely]

Thanks, I've updated the issue with a link to that paper. I suppose I should set it to status=Open and close this issue too though.

[tahonermann]

Per #2187 (comment), SG16 approved forwarding P3395R0 to LEWG with some requested changes. Those changes appear to have been addressed in P3395R1.

Removing the SG16 label; this is cleared for LWG.