[clang-tidy] Concatenate nested namespaces (4/7: components n-r) (#16301)

esphome/components/pid/pid_controller.cpp

@@ -1,7 +1,6 @@
 #include "pid_controller.h"
 
-namespace esphome {
-namespace pid {
+namespace esphome::pid {
 
 float PIDController::update(float setpoint, float process_value) {
   // e(t) ... error at timestamp t
@@ -123,5 +122,4 @@ float PIDController::calculate_relative_time_() {
   return dt / 1000.0f;
 }
 
-}  // namespace pid
-}  // namespace esphome
+}  // namespace esphome::pid