Fix reference in abstract class note

[leni536]

Referenced normative wording moved since [P0929R2].

[jensmaurer]

Looks like the CI build on MacOS is broken:

2026-03-05T07:42:11.8142010Z ! LaTeX Error: Command \tref undefined.
2026-03-05T07:42:11.8142270Z 
2026-03-05T07:42:11.8142470Z See the LaTeX manual or LaTeX Companion for explanation.
2026-03-05T07:42:11.8143270Z Type  H <return>  for immediate help.
2026-03-05T07:42:11.8143660Z  ...                                              
2026-03-05T07:42:11.8144040Z                                                   
2026-03-05T07:42:11.8144330Z l.409 \renewcommand{\tref}
2026-03-05T07:42:11.8144710Z                           [1]{\hyperref[tab:#1]{\tablerefname \nolinebreak[3...
2026-03-05T07:42:11.8145020Z 
2026-03-05T07:42:11.8145180Z ? 
2026-03-05T07:42:11.8145400Z ! Emergency stop.
2026-03-05T07:42:11.8145650Z  ...                                              
2026-03-05T07:42:11.8145940Z                                                   
2026-03-05T07:42:11.8146240Z l.409 \renewcommand{\tref}
2026-03-05T07:42:11.8146550Z                           [1]{\hyperref[tab:#1]{\tablerefname \nolinebreak[3...
2026-03-05T07:42:11.8146860Z 
2026-03-05T07:42:11.8147050Z !  ==> Fatal error occurred, no output PDF file produced!

@tkoeppe , any ideas?

[tkoeppe]

Let me take a look. Please don't merge anything for the time being.

[jwakely]

The first one that failed was https://github.com/cplusplus/draft/actions/runs/22566537777/job/65363813027 but it looked like a package version problem