Update sprinkler.rst to new style esp32 platform (#4695)

Author: shvmm

components/sprinkler.rst

@@ -643,7 +643,8 @@ could easily be added by adding the ``pump_switch_id`` parameter and a :ref:`swi
 
     esphome:
         name: esp-sprinkler-controller
-        platform: ESP32
+
+    esp32:
         board: featheresp32
 
     wifi:
@@ -673,7 +674,8 @@ This example illustrates a complete, simple three-valve system with no pump/upst
 
     esphome:
         name: esp-sprinkler-controller
-        platform: ESP32
+
+    esp32:
         board: featheresp32
 
     wifi:
@@ -724,7 +726,8 @@ This example illustrates a complete three-valve system with a single pump/upstre
 
     esphome:
         name: esp-sprinkler-controller
-        platform: ESP32
+
+    esp32:
         board: featheresp32
 
     wifi:
@@ -788,7 +791,8 @@ a common pump/upstream valve.
 
     esphome:
       name: esp-sprinkler-controller
-      platform: ESP32
+
+    esp32:
       board: featheresp32
 
     wifi:
@@ -866,7 +870,8 @@ valves, each of which are shared between the two controllers:
 
     esphome:
         name: esp-sprinkler-controller
-        platform: ESP32
+
+    esp32:
         board: featheresp32
 
     wifi: