Upgrade Rust and fix clippy issues (#2717)

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.82.0"
+channel = "1.83.0"
 targets = ["wasm32-unknown-unknown"]

src/canister_tests/src/api/internet_identity.rs

@@ -1,3 +1,4 @@
+//! The functions here are derived (manually) from Internet Identity's Candid file
 use candid::Principal;
 use ic_cdk::api::management_canister::main::CanisterId;
 use internet_identity_interface::archive::types::BufferedEntry;
@@ -11,8 +12,6 @@ pub mod api_v2;
 // API of verifiable credentials MVP.
 pub mod vc_mvp;
 
-/** The functions here are derived (manually) from Internet Identity's Candid file */
-
 /// A fake "health check" method that just checks the canister is alive a well.
 pub fn health_check(env: &PocketIc, canister_id: CanisterId) {
     let user_number: types::AnchorNumber = 0;

src/internet_identity/src/anchor_management/registration/captcha.rs

@@ -87,7 +87,7 @@ pub fn random_string<T: RngCore>(rng: &mut T, n: usize) -> String {
         chars.push(next);
     }
 
-    return String::from_utf8_lossy(&chars).to_string();
+    String::from_utf8_lossy(&chars).to_string()
 }
 
 #[cfg(feature = "dummy_captcha")]