fix clippy

Author: loongs-zhang

core/src/coroutine/korosensei.rs

@@ -58,7 +58,7 @@ impl<'c, Param, Yield, Return> Coroutine<'c, Param, Yield, Return> {
                             target_arch = "x86",
                         ))] {
                             let sp = context.uc_mcontext.gregs[usize::try_from(libc::REG_ESP)
-                                .unwrap_or_else(|| panic!("{} overflow", libc::REG_ESP))].try_into().unwrap();
+                                .unwrap_or_else(|_| panic!("{} overflow", libc::REG_ESP))].try_into().unwrap();
                         } else if #[cfg(all(target_vendor = "apple", target_arch = "x86_64"))] {
                             let sp = u64::try_from((*context.uc_mcontext).__ss.__rsp).expect("overflow");
                         } else if #[cfg(all(