landlock: Switch to the 2021 Rust edition

Cosmetic changes to format string following Clippy 1.66.0 suggestions:
https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args

Signed-off-by: Mickaël Salaün <mic@digikod.net>

Cargo.toml

@@ -5,7 +5,7 @@ authors = [
 	"Mickaël Salaün <mic@digikod.net>",
 	"Vincent Dagonneau <vincentdagonneau@gmail.com>"
 ]
-edition = "2018"
+edition = "2021"
 rust-version = "1.63"
 description = "Landlock LSM helpers"
 homepage = "https://landlock.io"

src/compat.rs

@@ -116,11 +116,11 @@ lazy_static! {
             if ABI::is_known(n) || n == 0 {
                 ABI::from(n)
             } else {
-                panic!("Unknown ABI: {}", n);
+                panic!("Unknown ABI: {n}");
             }
         }
         Err(std::env::VarError::NotPresent) => ABI::iter().last().unwrap(),
-        Err(e) => panic!("Failed to read LANDLOCK_CRATE_TEST_ABI: {}", e),
+        Err(e) => panic!("Failed to read LANDLOCK_CRATE_TEST_ABI: {e}"),
     };
 }
 

src/lib.rs

@@ -121,7 +121,7 @@ mod tests {
             let ret = check(Ruleset::from(abi));
 
             // Useful for failed tests and with cargo test -- --show-output
-            println!("Checking ABI {:?}, expecting {:#?}", abi, ret);
+            println!("Checking ABI {abi:?}, expecting {ret:#?}");
             if can_emulate(abi, full) {
                 if abi < partial && error_if_abi_lt_partial {
                     // TODO: Check exact error type; this may require better error types.