Replace raw-type uses of Post with Post<?>.

Change-Id: I3ba2094ea9471d8d86af7c8d6a537d7eb43961de
diff --git a/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java b/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java
index 3a16868..f783ba0 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java
@@ -413,7 +413,7 @@
     if (!(o instanceof Post)) {
       return false;
     }
-    Post post = (Post) o;
+    Post<?> post = (Post<?>) o;
     return Objects.equals(id, post.id);
   }
 
diff --git a/src/main/java/eu/mulk/mulkcms2/benki/posts/PostResource.java b/src/main/java/eu/mulk/mulkcms2/benki/posts/PostResource.java
index 7ecfcba..c0d8647 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/posts/PostResource.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/posts/PostResource.java
@@ -202,7 +202,7 @@
   @GET
   @Produces(APPLICATION_JSON)
   @Path("{id}")
-  public Post getPostJson(@PathParam("id") int id) {
+  public Post<?> getPostJson(@PathParam("id") int id) {
     return getPostIfVisible(id);
   }
 
@@ -443,7 +443,7 @@
     return entityManager.unwrap(Session.class);
   }
 
-  protected static void assignPostTargets(Post.Visibility visibility, User user, Post post) {
+  protected static void assignPostTargets(Post.Visibility visibility, User user, Post<?> post) {
     switch (visibility) {
       case PUBLIC:
         post.targets = Set.of(Role.getWorld());
@@ -459,7 +459,7 @@
     }
   }
 
-  protected final Post getPostIfVisible(int id) {
+  protected final Post<?> getPostIfVisible(int id) {
     @CheckForNull var user = getCurrentUser();
     var message = getSession().byId(Post.class).load(id);