Rust BPF program cleanup (#7990)

programs/bpf/rust/dup_accounts/src/lib.rs

@@ -8,7 +8,7 @@ use solana_sdk::{
 entrypoint!(process_instruction);
 fn process_instruction(
     _program_id: &Pubkey,
-    accounts: &mut [AccountInfo],
+    accounts: &[AccountInfo],
     instruction_data: &[u8],
 ) -> u32 {
     const FAILURE: u32 = 1;