Document template.select platform (#19062)

Co-authored-by: Franck Nijhof <git@frenck.dev>

source/_integrations/template.markdown

@@ -11,7 +11,6 @@ ha_codeowners:
   - '@home-assistant/core'
   - '@PhracturedBlue'
   - '@tetienne'
-  - '@home-assistant/core'
 ha_domain: template
 ha_platforms:
   - alarm_control_panel
@@ -21,6 +20,7 @@ ha_platforms:
   - light
   - lock
   - number
+  - select
   - sensor
   - switch
   - vacuum
@@ -29,7 +29,7 @@ ha_platforms:
 
 The `template` integration allows creating entities which derive their values from other data. This is done by specifying [templates](/docs/configuration/templating/) for properties of an entity, like the name or the state.
 
-Sensors, binary (on/off) sensors, and numbers are covered on this page. For other types, please see the specific pages:
+Sensors, binary (on/off) sensors, numbers and selects are covered on this page. For other types, please see the specific pages:
 
 - [Alarm Control Panel](/integrations/alarm_control_panel.template/)
 - [Cover](/integrations/cover.template/)
@@ -40,7 +40,7 @@ Sensors, binary (on/off) sensors, and numbers are covered on this page. For othe
 - [Vacuum](/integrations/vacuum.template/)
 - [Weather](/integrations/weather.template/)
 
-Sensor, binary sensor, and number template entities are defined in your YAML configuration files, directly under the `template:` key and cannot be configured via the UI. You can define multiple configuration blocks as a list. Each block defines sensor/binary sensor/number entities and can contain an optional update trigger.
+Sensor, binary sensor, number and select template entities are defined in your YAML configuration files, directly under the `template:` key and cannot be configured via the UI. You can define multiple configuration blocks as a list. Each block defines sensor/binary sensor/number entities and can contain an optional update trigger.
 
 _For old sensor/binary sensor configuration format, [see below](#legacy-binary-sensor-configuration-format)._
 
@@ -201,7 +201,29 @@ number:
       required: false
       type: boolean
       default: false
-"[all sensor, binary sensor, number entities]":
+select:
+  description: List of selects
+  required: true
+  type: map
+  keys:
+    state:
+      description: Template for the select's current value.
+      required: true
+      type: template
+    select_option:
+      description: Defines an action to run to select an option from the `options` list.
+      required: true
+      type: action
+    options:
+      description: Template for the select's available options.
+      required: true
+      type: template
+    optimistic:
+      description: Flag that defines if select works in optimistic mode.
+      required: false
+      type: boolean
+      default: false
+"[all sensor, binary sensor, number, select entities]":
   description: Fields that can be used above for sensors, binary sensors, and numbers.
   required: false
   type: map
@@ -211,11 +233,11 @@ number:
       required: false
       type: template
     unique_id:
-      description: "An ID that uniquely identifies this sensor. Will be combined with the unique ID of the configuration block if available. This allows changing the `name`, `icon` and `entity_id` from the web interface."
+      description: An ID that uniquely identifies this sensor. Will be combined with the unique ID of the configuration block if available. This allows changing the `name`, `icon` and `entity_id` from the web interface.
       required: false
       type: string
     availability:
-      description: "Defines a template to get the `available` state of the component. If the template returns `true`, the device is `available`. If the template returns any other value, the device will be `unavailable`. If not configured, the component will always be `available`."
+      description: Defines a template to get the `available` state of the component. If the template returns `true`, the device is `available`. If the template returns any other value, the device will be `unavailable`. If not configured, the component will always be `available`.
       required: false
       type: template
       default: true