Add post for 1.77

[Mark-Simulacrum]

cc @rust-lang/release

[lcnr]

I think one of the biggest changes in 1.77 is rust-lang/rust#117703.

We now support recursive async functions (as long as they use indirection), making the async-recursion crate unnecessary.

before:

use async_recursion::async_recursion;

#[async_recursion]
async fn fib(n : u32) -> u32 {
   match n {
      0 | 1 => 1,
      _ => fib(n-1).await + fib(n-2).await
   }
}
// which expands to
use std::future::Future;
use std::pin::Pin;

fn fib(n: u32) -> Pin<Box<dyn Future<Output = u32> + Send>> {
    Box::pin(async move {
        match n {
            0 | 1 => 1,
            _ => fib(n - 1).await + fib(n - 2).await,
        }
    })
}

after

async fn fib(n : u32) -> u32 {
   match n {
       0 | 1 => 1,
       _ => Box::pin(fib(n-1)).await + Box::pin(fib(n-2)).await
   }
}

By avoiding trait objects this should improve the runtime performance of such functions and avoids the "auto-trait bound" problem of async-recursion by leaking the Send bound (and all other auto traits) automatically.

[Mark-Simulacrum]

Alright, I think this is now updated per all the feedback here. Thanks!