Remove all eight DiagnosticBuilder::*_with_code methods.

These all have relatively low use, and can be perfectly emulated with
a simpler construction method combined with `code` or `code_mv`.

compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs

@@ -523,8 +523,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
     fn start_diagnostics(&self) -> DiagnosticBuilder<'tcx> {
         let span = self.path_segment.ident.span;
         let msg = self.create_error_message();
-
-        self.tcx.dcx().struct_span_err_with_code(span, msg, self.code())
+        self.tcx.dcx().struct_span_err(span, msg).code_mv(self.code())
     }
 
     /// Builds the `expected 1 type argument / supplied 2 type arguments` message.