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

esphome/components/bme680_bsec/bme680_bsec.cpp

@@ -3,8 +3,7 @@
 #include "esphome/core/log.h"
 #include <string>
 
-namespace esphome {
-namespace bme680_bsec {
+namespace esphome::bme680_bsec {
 #ifdef USE_BSEC
 static const char *const TAG = "bme680_bsec.sensor";
 
@@ -565,5 +564,4 @@ void BME680BSECComponent::save_state_(uint8_t accuracy) {
   ESP_LOGI(TAG, "Saved state");
 }
 #endif
-}  // namespace bme680_bsec
-}  // namespace esphome
+}  // namespace esphome::bme680_bsec