Add a description for BIOS boot sector crate

Author: phil-opp

bios/boot_sector/Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Philipp Oppermann <dev@phil-opp.com>"]
 edition = "2021"
 license.workspace = true
 repository.workspace = true
+description = "BIOS boot sector for the `bootloader` crate"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html