Move some Map methods onto TyCtxt.

The end goal is to eliminate `Map` altogether.

I added a `hir_` prefix to all of them, that seemed simplest. The
exceptions are `module_items` which became `hir_module_free_items` because
there was already a `hir_module_items`, and `items` which became
`hir_free_items` for consistency with `hir_module_free_items`.

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -679,7 +679,7 @@ fn infringing_fields_error<'tcx>(
 
     suggest_constraining_type_params(
         tcx,
-        tcx.hir().get_generics(impl_did).expect("impls always have generics"),
+        tcx.hir_get_generics(impl_did).expect("impls always have generics"),
         &mut err,
         bounds
             .iter()

compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs

@@ -25,7 +25,7 @@ pub(crate) fn crate_inherent_impls(
     let mut collect = InherentCollect { tcx, impls_map: Default::default() };
 
     let mut res = Ok(());
-    for id in tcx.hir().items() {
+    for id in tcx.hir_free_items() {
         res = res.and(collect.check_item(id));
     }
 

compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs

@@ -18,7 +18,7 @@ pub(crate) fn crate_inherent_impls_overlap_check(
 ) -> Result<(), ErrorGuaranteed> {
     let mut inherent_overlap_checker = InherentOverlapChecker { tcx };
     let mut res = Ok(());
-    for id in tcx.hir().items() {
+    for id in tcx.hir_free_items() {
         res = res.and(inherent_overlap_checker.check_item(id));
     }
     res