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_parse/src/parser/diagnostics.rs

@@ -2847,8 +2847,8 @@ impl<'a> Parser<'a> {
         let span = label.ident.span.to(self.prev_token.span);
         self.dcx()
             .struct_span_err(span, "block label not supported here")
-            .span_label_mv(span, "not supported here")
-            .tool_only_span_suggestion_mv(
+            .with_span_label(span, "not supported here")
+            .with_tool_only_span_suggestion(
                 label.ident.span.until(self.token.span),
                 "remove this block label",
                 "",