Fix clippy warnings.

This commit fixes the current set of (stable) clippy warnings in the repo.

cranelift/wasm/src/state/module_state.rs

@@ -2,6 +2,10 @@ use crate::translation_utils::SignatureIndex;
 use cranelift_entity::PrimaryMap;
 use std::boxed::Box;
 
+/// Map of signatures to a function's parameter and return types.
+pub(crate) type WasmTypes =
+    PrimaryMap<SignatureIndex, (Box<[wasmparser::Type]>, Box<[wasmparser::Type]>)>;
+
 /// Contains information decoded from the Wasm module that must be referenced
 /// during each Wasm function's translation.
 ///
@@ -14,14 +18,13 @@ pub struct ModuleTranslationState {
     ///
     /// This is used for translating multi-value Wasm blocks inside functions,
     /// which are encoded to refer to their type signature via index.
-    pub(crate) wasm_types:
-        PrimaryMap<SignatureIndex, (Box<[wasmparser::Type]>, Box<[wasmparser::Type]>)>,
+    pub(crate) wasm_types: WasmTypes,
 }
 
 impl ModuleTranslationState {
     /// Creates a new empty ModuleTranslationState.
     pub fn new() -> Self {
-        ModuleTranslationState {
+        Self {
             wasm_types: PrimaryMap::new(),
         }
     }