Update some comments

[ChrisDenton]

I've replaced the comment about MSVC in src/backtrace/dbghelp*.rs as the same code is used for windows-gnu, see

backtrace-rs/src/backtrace/mod.rs

Lines 169 to 199 in 5e05efa

	if #[cfg(miri)] {
	pub(crate) mod miri;
	use self::miri::trace as trace_imp;
	pub(crate) use self::miri::Frame as FrameImp;
	} else if #[cfg(
	any(
	all(
	unix,
	not(target_os = "emscripten"),
	not(all(target_os = "ios", target_arch = "arm")),
	not(all(target_os = "nto", target_env = "nto70")),
	),
	all(
	target_env = "sgx",
	target_vendor = "fortanix",
	),
	)
	)] {
	mod libunwind;
	use self::libunwind::trace as trace_imp;
	pub(crate) use self::libunwind::Frame as FrameImp;
	} else if #[cfg(all(windows, not(target_vendor = "uwp")))] {
	cfg_if::cfg_if! {
	if #[cfg(any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "arm64ec"))] {
	mod dbghelp64;
	use dbghelp64 as dbghelp;
	} else if #[cfg(any(target_arch = "x86", target_arch = "arm"))] {
	mod dbghelp32;
	use dbghelp32 as dbghelp;
	}
	}

[ChrisDenton]

And now that I look at dbghelp64.rs, it doesn't actually use dbghelp.dll at all so the name is outdated. But I don't feel strongly about changing it.

[workingjubilee]

Thanks!