[Bug driver/90983] manual documents `-Wno-stack-usage` flag, but it is unrecognized

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90983

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
Using a very large -Wstack-usage argument should effectively disable the
warning.  E.g., -Wstack-usage=4EiB or -Wstack-usage=$(getconf ULONG_MAX).