Rename supertraits of CodegenMethods.

Supertraits of `BuilderMethods` are all called `XyzBuilderMethods`.
Supertraits of `CodegenMethods` are all called `XyzMethods`. This commit
changes the latter to `XyzCodegenMethods`, for consistency.

compiler/rustc_codegen_gcc/src/declare.rs

@@ -1,7 +1,7 @@
 #[cfg(feature = "master")]
 use gccjit::{FnAttribute, ToRValue};
 use gccjit::{Function, FunctionType, GlobalKind, LValue, RValue, Type};
-use rustc_codegen_ssa::traits::BaseTypeMethods;
+use rustc_codegen_ssa::traits::BaseTypeCodegenMethods;
 use rustc_middle::ty::Ty;
 use rustc_span::Symbol;
 use rustc_target::abi::call::FnAbi;