Rename consuming chaining methods on DiagnosticBuilder.

In #119606 I added them and used a `_mv` suffix, but that wasn't great.

A `with_` prefix has three different existing uses.
- Constructors, e.g. `Vec::with_capacity`.
- Wrappers that provide an environment to execute some code, e.g.
  `with_session_globals`.
- Consuming chaining methods, e.g. `Span::with_{lo,hi,ctxt}`.

The third case is exactly what we want, so this commit changes
`DiagnosticBuilder::foo_mv` to `DiagnosticBuilder::with_foo`.

Thanks to @compiler-errors for the suggestion.

compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs

@@ -523,7 +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(span, msg).code_mv(self.code())
+        self.tcx.dcx().struct_span_err(span, msg).with_code(self.code())
     }
 
     /// Builds the `expected 1 type argument / supplied 2 type arguments` message.