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_session/src/errors.rs

@@ -19,8 +19,8 @@ impl<'a> IntoDiagnostic<'a> for FeatureGateError {
     #[track_caller]
     fn into_diagnostic(self, dcx: &'a DiagCtxt, level: Level) -> DiagnosticBuilder<'a> {
         DiagnosticBuilder::new(dcx, level, self.explain)
-            .span_mv(self.span)
-            .code_mv(error_code!(E0658))
+            .with_span(self.span)
+            .with_code(error_code!(E0658))
     }
 }
 

compiler/rustc_session/src/session.rs

@@ -1488,7 +1488,7 @@ impl EarlyDiagCtxt {
             #[allow(rustc::diagnostic_outside_of_impl)]
             self.dcx
                 .struct_warn(err)
-                .note_mv("the build environment is likely misconfigured")
+                .with_note("the build environment is likely misconfigured")
                 .emit()
         });
     }