doc(keyboard): add deprecated warning

man/waybar-keyboard-state.5.scd

@@ -13,6 +13,7 @@ You must be a member of the input group to use this module.
 # CONFIGURATION
 
 *interval*: ++
+	Deprecated, this module use event loop now, the interval has no effect.
 	typeof: integer ++
 	default: 1 ++
 	The interval, in seconds, to poll the keyboard state.

src/modules/keyboard_state.cpp

@@ -110,6 +110,10 @@ waybar::modules::KeyboardState::KeyboardState(const std::string& id, const Bar&
   static struct libinput_interface interface = {
       [](const char* path, int flags, void* user_data) { return open(path, flags); },
       [](int fd, void* user_data) { close(fd); }};
+  if (config_["interval"].isUInt()) {
+    spdlog::warn("keyboard-state: interval is deprecated");
+  }
+
   libinput_ = libinput_path_create_context(&interface, NULL);
 
   box_.set_name("keyboard-state");