Fixed missing API reference generation for some functions by adding JUCE_MODAL_LOOPS_PERMITTED=1 to predefines in Doxyfile.

doxygen/Doxyfile

@@ -2058,7 +2058,8 @@ PREDEFINED             = WIN32=1 \
                          JUCE_COMPILER_SUPPORTS_MOVE_SEMANTICS=1 \
                          JUCE_COMPILER_SUPPORTS_INITIALIZER_LISTS=1 \
                          JUCE_COMPILER_SUPPORTS_VARIADIC_TEMPLATES=1 \
-                         JUCE_COMPILER_SUPPORTS_OVERRIDE_AND_FINAL=1
+                         JUCE_COMPILER_SUPPORTS_OVERRIDE_AND_FINAL=1 \
+                         JUCE_MODAL_LOOPS_PERMITTED=1
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The