[clang-tidy] Concatenate nested namespaces (1/7: components a-c) (#16294)

esphome/components/airthings_wave_plus/airthings_wave_plus.cpp

@@ -2,8 +2,7 @@
 
 #ifdef USE_ESP32
 
-namespace esphome {
-namespace airthings_wave_plus {
+namespace esphome::airthings_wave_plus {
 
 static const char *const TAG = "airthings_wave_plus";
 
@@ -98,7 +97,6 @@ void AirthingsWavePlus::setup() {
       espbt::ESPBTUUID::from_raw(access_control_point_characteristic_uuid);
 }
 
-}  // namespace airthings_wave_plus
-}  // namespace esphome
+}  // namespace esphome::airthings_wave_plus
 
 #endif  // USE_ESP32