Qt has Q_DECL_DEPRECATED_X defined in src/corelib/global/qcompilerdetection.h as __attribute__ ((__deprecated__(text))) (on compilers that support it, it's a C++14 feature), which is quite convenient for people hitting a deprecation warning.
Our deprecated macros come from cmake's GenerateExportHeader.cmake which doesn't support adding such a suggestion text.
But while writing this, I just saw D23789 which forks that into ECM anyway....