Rollup merge of #77452 - Mark-Simulacrum:fix-symbol-v0, r=eddyb

Permit ty::Bool in const generics for v0 mangling

This should unbreak using new-symbol-mangling = true in config.toml (once it lands in beta anyway).

Fixes #76365 (well, it will, but seems fine to close as soon as we have support)

r? @eddyb (for mangling) but I'm okay with some other reviewer too :)

compiler/rustc_symbol_mangling/src/v0.rs

@@ -504,6 +504,7 @@ impl Printer<'tcx> for SymbolMangler<'tcx> {
 
         match ct.ty.kind() {
             ty::Uint(_) => {}
+            ty::Bool => {}
             _ => {
                 bug!("symbol_names: unsupported constant of type `{}` ({:?})", ct.ty, ct);
             }