remove FIXME(#13101) since `assert_receiver_is_total_eq` stays.
remove FIXME(#19649) now that stability markers render.
remove FIXME(#13642) now the benchmarks were moved.
remove FIXME(#6220) now that floating points can be formatted.
remove FIXME(#18248) and write tests for `Rc<str>` and `Rc<[u8]>`
remove reference to irelevent issues in FIXME(#1697, #2178...)
update FIXME(#5516) to point to getopts issue 7
update FIXME(#7771) to point to RFC 628
update FIXME(#19839) to point to issue 26925
You can otherwise end up in a situation where you don't actually resize
but still call into handle_cap_increase which then corrupts head/tail.
Closes#44800
The previous documentation mentioned this, but ambiguously used the term "fail".
This clarifies that the function will panic if the index is out of bounds, instead of silently failing and not doing anything.
