rust: add example for alias argument in module macro documentation

Add example for `alias` argument supported by `module` macro.
`alias` accepts an array of alternate names for the module as string.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Aswin Unnikrishnan <aswinunni01@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Link: https://lore.kernel.org/r/20240512112324.8514-1-aswinunni01@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: aswinunni01

rust/macros/lib.rs

@@ -35,6 +35,7 @@ use proc_macro::TokenStream;
 ///     author: "Rust for Linux Contributors",
 ///     description: "My very own kernel module!",
 ///     license: "GPL",
+///     alias: ["alternate_module_name"],
 /// }
 ///
 /// struct MyModule;