Move trait selection error reporting to its own top-level module

compiler/rustc_trait_selection/src/solve/normalize.rs

@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 use std::marker::PhantomData;
 
-use crate::traits::error_reporting::{OverflowCause, TypeErrCtxtExt};
+use crate::error_reporting::traits::{OverflowCause, TypeErrCtxtExt};
 use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::{BoundVarReplacer, PlaceholderReplacer, ScrubbedTraitError};
 use rustc_data_structures::stack::ensure_sufficient_stack;