Switch from doc(include) to doc = include_str!

[jyn514]

I plan to deprecate doc(include) in the near future, and rust-lang/rust denies warnings in CI.

cc rust-lang/rust#78835 (comment), rust-lang/rust#44732 (comment)

[rust-highfive]

r? @Amanieu

(rust-highfive has picked a reviewer for you, use r? to override)

[jyn514]

The test failure looks unrelated.

failures:

---- core_arch::x86::sse2::tests::test_mm_storeu_pd stdout ----
thread 'core_arch::x86::sse2::tests::test_mm_storeu_pd' panicked at 'assertion failed: `(left == right)`
  left: `0.0`,
 right: `1.0`', crates/core_arch/src/x86/sse2.rs:4747:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[Amanieu]

CI should be fixed by #1015, try rebasing.

[jyn514]

Thanks, done.