Minor documentation fixes

modules/juce_core/memory/juce_ReferenceCountedObject.h

@@ -226,6 +226,7 @@ private:
     {
         typedef ReferenceCountedObjectPtr<MyClass> Ptr;
         ...
+    }
     @endcode
 
     @see ReferenceCountedObject, ReferenceCountedObjectArray

modules/juce_core/xml/juce_XmlDocument.h

@@ -55,6 +55,7 @@ namespace juce
     if (xml != nullptr && xml->hasTagName ("foobar"))
     {
         ...etc
+    }
     @endcode
 
     @see XmlElement

modules/juce_product_unlocking/in_app_purchases/juce_InAppPurchases.h

@@ -184,13 +184,15 @@ public:
     bool isInAppPurchasesSupported() const;
 
     /** Asynchronously requests information for products with given ids. Upon completion, for each enquired product
-        there is going to be a corresponding @class Product object.
+        there is going to be a corresponding Product object.
         If there is no information available for the given product identifier, it will be ignored.
      */
     void getProductsInformation (const StringArray& productIdentifiers);
 
     /** Asynchronously requests to buy a product with given id.
 
+        @param productIdentifier               The product identifier.
+
         @param isSubscription                  (Android only) defines if a product a user wants to buy is a subscription or a one-time purchase.
                                                On iOS, type of the product is derived implicitly.