doc: extend About section with Example Use Cases

Author: phip1611

uefi/src/lib.rs

@@ -20,11 +20,24 @@
 //! _Note that for producing EFI images, you also need to use a corresponding
 //! `uefi` compiler target of Rust, such as `x86_64-unknown-uefi`._
 //!
-//! # Interaction with uefi services
+//! ## Use Cases
 //!
-//! With this crate you can write code for the pre- and post-exit boot services
-//! epochs. However, the `uefi` crate unfolds its true potential when
-//! interacting with UEFI boot services.
+//! This crate allows you to write code for both pre- and post-exit boot
+//! services phases. However, its true strength shines when creating EFI images
+//! that interact with UEFI boot services and ultimately exit them.
+//!
+//! When we mention EFI images, we're talking about EFI applications, EFI boot
+//! service drivers, and EFI runtime service drivers, which typically have the
+//! `.efi` file extension. For instance, an EFI application could be an
+//! OS-specific loader, similar to _GRUB_ or _Limine_.
+//!
+//! Additionally, you can use this crate with non-EFI images (such as a kernel
+//! in ELF format) to perform tasks like parsing the UEFI memory map embedded in
+//! the boot information provided by a bootloader, such as _GRUB_ or _Limine_.
+//! It also enables access to UEFI runtime services from a non-EFI image kernel.
+//!
+//! In summary, `uefi` is addressing the entire spectrum of your development
+//! needs
 //!
 //! ## Supported Architectures
 //!