Make the _hook_use aliases emit a deprecation warning

Turn `event_handler_hook_use` and `loop_hook_use` into real functions, so that
we can apply a `deprecated` attribute, which in turn will emit a compile-time
warning when either of these functions are used.

Signed-off-by: Gergely Nagy <kaleidoscope@gergo.csillger.hu>

src/Kaleidoscope.cpp

@@ -134,3 +134,13 @@ Kaleidoscope_::focusHook(const char *command) {
 }
 
 Kaleidoscope_ Kaleidoscope;
+
+/* Deprecated functions */
+
+void event_handler_hook_use(Kaleidoscope_::eventHandlerHook hook) {
+  Kaleidoscope.useEventHandlerHook(hook);
+}
+
+void loop_hook_use(Kaleidoscope_::loopHook hook) {
+  Kaleidoscope.useLoopHook(hook);
+}

src/Kaleidoscope.h

@@ -121,5 +121,5 @@ extern Kaleidoscope_ Kaleidoscope;
 
 /* -- DEPRECATED aliases; remove them when there are no more users. -- */
 
-#define event_handler_hook_use(hook) Kaleidoscope.useEventHandlerHook(hook);
+void event_handler_hook_use(Kaleidoscope_::eventHandlerHook hook) __attribute__((deprecated));
-#define loop_hook_use(hook) Kaleidoscope.useLoopHook(hook)
+void loop_hook_use(Kaleidoscope_::loopHook hook) __attribute__((deprecated));