Docs: Replace doxygen preprocessor conditionals with @cond and @endconds

modules/juce_data_structures/values/juce_ValueTree.h

@@ -617,10 +617,12 @@ public:
     */
     int getReferenceCount() const noexcept;
 
-   #if JUCE_ALLOW_STATIC_NULL_VARIABLES && ! defined (DOXYGEN)
+   #if JUCE_ALLOW_STATIC_NULL_VARIABLES
+    /** @cond */
     /* An invalid ValueTree that can be used if you need to return one as an error condition, etc. */
     [[deprecated ("If you need an empty ValueTree object, just use ValueTree() or {}.")]]
     static const ValueTree invalid;
+    /** @endcond */
    #endif
 
 private:

modules/juce_data_structures/values/juce_ValueTreePropertyWithDefault.h

@@ -335,11 +335,11 @@ private:
 };
 
 //==============================================================================
-#ifndef DOXYGEN
+/** @cond */
 using ValueWithDefault  [[deprecated ("This class has been renamed to better describe what is does. "
                                       "This declaration is here for backwards compatibility and new "
                                       "code should use the new class name.")]]
     = ValueTreePropertyWithDefault;
-#endif
+/** @endcond */
 
 } // namespace juce