[clang-tidy] Concatenate nested namespaces (3/7: components i-m) (#16297)

esphome/components/integration/integration_sensor.cpp

@@ -3,8 +3,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-namespace esphome {
-namespace integration {
+namespace esphome::integration {
 
 static const char *const TAG = "integration";
 
@@ -47,5 +46,4 @@ void IntegrationSensor::process_sensor_value_(float value) {
   this->publish_and_save_(this->result_ + area);
 }
 
-}  // namespace integration
-}  // namespace esphome
+}  // namespace esphome::integration