Fix AnyRef and AnyInitializer constructors to exclude not only exact

conflicts with the move constructor, but also conflicts with materializing the
given object from `Initializer` etc.

This way constructing `AnyRef<Handle>` from `Initializer<AnyRef<Handle>>` is
done by materializing the `AnyRef<Handle>`, instead of wrapping a reference to
it. The latter might not work anyway because it could store a reference to an
object which is getting destroyed too soon, which is caught by
`ABSL_ATTRIBUTE_LIFETIME_BOUND`.

Cosmetics: remove old-style `absl_nullability_compatible` tag which does not
have any effect since
abseil/abseil-cpp@485f2be
and was left here by mistake.
PiperOrigin-RevId: 697950999

riegeli/base/any.h

@@ -392,16 +392,14 @@ class
 #endif
         AnyRef : public any_internal::AnyBase<Handle, 0, 0> {
  public:
-  using absl_nullability_compatible = void;
-
   // Creates an empty `AnyRef`.
   AnyRef() noexcept { this->Initialize(); }
 
   // Holds a `Dependency<Handle, Manager&&>`.
   template <typename Manager,
             std::enable_if_t<
                 absl::conjunction<
-                    absl::negation<std::is_same<std::decay_t<Manager>, AnyRef>>,
+                    absl::negation<std::is_same<TargetT<Manager>, AnyRef>>,
                     SupportsDependency<Handle, Manager&&>>::value,
                 int> = 0>
   /*implicit*/ AnyRef(Manager&& manager ABSL_ATTRIBUTE_LIFETIME_BOUND);
@@ -719,7 +717,7 @@ template <
     typename Manager,
     std::enable_if_t<
         absl::conjunction<
-            absl::negation<std::is_same<std::decay_t<Manager>, AnyRef<Handle>>>,
+            absl::negation<std::is_same<TargetT<Manager>, AnyRef<Handle>>>,
             SupportsDependency<Handle, Manager&&>>::value,
         int>>
 inline AnyRef<Handle>::AnyRef(Manager&& manager ABSL_ATTRIBUTE_LIFETIME_BOUND) {

riegeli/base/any_initializer.h

@@ -65,9 +65,9 @@ class AnyInitializer {
   template <
       typename Manager,
       std::enable_if_t<
-          absl::conjunction<absl::negation<std::is_same<std::decay_t<Manager>,
-                                                        AnyInitializer>>,
-                            TargetSupportsDependency<Handle, Manager>>::value,
+          absl::conjunction<
+              absl::negation<std::is_same<TargetT<Manager>, AnyInitializer>>,
+              TargetSupportsDependency<Handle, Manager>>::value,
           int> = 0>
   /*implicit*/ AnyInitializer(Manager&& manager ABSL_ATTRIBUTE_LIFETIME_BOUND)
       : construct_(ConstructMethod<Manager>),