Add debug output when ignoring key press during IME

glfw/cocoa_window.m

@@ -1181,6 +1181,7 @@ - (void)keyDown:(NSEvent *)event
         }
         if (([self hasMarkedText] || previous_has_marked_text) && !_glfw.ns.text[0]) {
             // do not pass keys like BACKSPACE while there's pre-edit text, let IME handle it
+            debug_key("Ignoring key press as IME is active and it generated no text\n");
             return;
         }
     }