Remove io-lifetimes dep from doc; no longer used

doc/Cargo.toml

@@ -5,7 +5,6 @@ edition = "2018"
 publish = false
 
 [dependencies]
-io-lifetimes = "1.0.3"
 calloop = { path = "..", features = ["futures-io", "executor"] }
 anyhow = "1.0.56"
 futures = "0.3.21"

doc/src/ch02-01-generic.md

@@ -16,7 +16,7 @@ The easiest constructor to use is the [`new()`](api/calloop/generic/struct.Gener
 
 ## Ownership and AsFd wrappers
 
-Rust 1.63 introduced a concept of file descriptor ownership and borrowing through the `OwnedFd` and `BorrowedFd` types, which are also available on older Rust versions through the `io-lifetimes` crate. The `AsFd` trait provides a way to get a `BorrowedFd` corresponding to a file, socket, etc. while guaranteeing the fd will be valid for the lifetime of the `BorrowedFd`.
+Rust 1.63 introduced a concept of file descriptor ownership and borrowing through the `OwnedFd` and `BorrowedFd` types. The `AsFd` trait provides a way to get a `BorrowedFd` corresponding to a file, socket, etc. while guaranteeing the fd will be valid for the lifetime of the `BorrowedFd`.
 
 Not all third party crates use `AsFd` yet, and may instead provide types implementing `AsRawFd`. ['AsFdWrapper'](api/calloop/generic/struct.AsFdWrapper.html) provides a way to adapt these types. To use this safely, ensure the `AsRawFd` implementation of the type it wraps returns a valid fd as long as the type exists. And to avoid an fd leak, it should ultimately be `close`d properly.