spelling: variable

Signed-off-by: Josh Soref <2119212+jsoref@users.noreply.github.com>

Author: jsoref

cargo-miri/src/main.rs

@@ -81,7 +81,7 @@ fn main() {
         "miri" => phase_cargo_miri(args),
         "runner" => phase_runner(args, RunnerPhase::Cargo),
         arg if arg == env::var("RUSTC").unwrap() => {
-            // If the first arg is equal to the RUSTC env ariable (which should be set at this
+            // If the first arg is equal to the RUSTC env variable (which should be set at this
             // point), then we need to behave as rustc. This is the somewhat counter-intuitive
             // behavior of having both RUSTC and RUSTC_WRAPPER set
             // (see https://github.com/rust-lang/cargo/issues/10886).