core: Make variable shadowing a compile-time error

Now that we have most of core free of shadowing, we can enable the
warning as an error to catch anything that may be remaining and also
eliminate this class of logic bug entirely.

src/core/hle/service/pctl/pctl.cpp

@@ -7,8 +7,8 @@
 namespace Service::PCTL {
 
 PCTL::PCTL(Core::System& system_, std::shared_ptr<Module> module_, const char* name,
-           Capability capability)
-    : Interface{system_, std::move(module_), name, capability} {
+           Capability capability_)
+    : Interface{system_, std::move(module_), name, capability_} {
     static const FunctionInfo functions[] = {
         {0, &PCTL::CreateService, "CreateService"},
         {1, &PCTL::CreateServiceWithoutInitialize, "CreateServiceWithoutInitialize"},

src/core/hle/service/pctl/pctl.h

@@ -15,7 +15,7 @@ namespace Service::PCTL {
 class PCTL final : public Module::Interface {
 public:
     explicit PCTL(Core::System& system_, std::shared_ptr<Module> module_, const char* name,
-                  Capability capability);
+                  Capability capability_);
     ~PCTL() override;
 };