[format.syn] Bad index entry for format_args_t

[Eelis]

draft/source/utilities.tex

Line 15568 in 8c8e05d

\indexlibraryglobal{format_args_t}%

format_args_t is not mentioned in [format], but is mentioned in https://eel.is/c++draft/diff.cpp20.utilities#1.sentence-2

[cpplearner]

#6813 removes this index entry.

[Eelis]

Ah perfect!