Ignore CORRADE_DEPRECATED() macro in Doxygen.

Doxyfile

@@ -1611,7 +1611,7 @@ ENABLE_PREPROCESSING   = YES
 # compilation will be performed. Macro expansion can be done in a controlled
 # way by setting EXPAND_ONLY_PREDEF to YES.
 
-MACRO_EXPANSION        = NO
+MACRO_EXPANSION        = YES
 
 # If the EXPAND_ONLY_PREDEF and MACRO_EXPANSION tags are both set to YES
 # then the macro expansion is limited to the macros specified with the
@@ -1645,7 +1645,8 @@ INCLUDE_FILE_PATTERNS  =
 # undefined via #undef or recursively expanded use the := operator
 # instead of the = operator.
 
-PREDEFINED             = DOXYGEN_GENERATING_OUTPUT MAGNUM_BUILD_DEPRECATED
+PREDEFINED             = DOXYGEN_GENERATING_OUTPUT \
+    MAGNUM_BUILD_DEPRECATED CORRADE_DEPRECATED(message)=
 
 # 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.