Shorten some error invocations.

- `struct_foo` + `emit` -> `foo`
- `create_foo` + `emit` -> `emit_foo`

I have made recent commits in other PRs that have removed some of these
shortcuts for combinations with few uses, e.g.
`struct_span_err_with_code`. But for the remaining combinations that
have high levels of use, we might as well use them wherever possible.

compiler/rustc_resolve/src/late.rs

@@ -2301,7 +2301,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             let report_error = |this: &Self, ns| {
                 if this.should_report_errs() {
                     let what = if ns == TypeNS { "type parameters" } else { "local variables" };
-                    this.r.dcx().create_err(ImportsCannotReferTo { span: ident.span, what }).emit();
+                    this.r.dcx().emit_err(ImportsCannotReferTo { span: ident.span, what });
                 }
             };