Add improv serial next_url (#2620)

components/improv_serial.rst

@@ -20,7 +20,26 @@ The ``improv_serial`` component requires the serial ``logger`` to be configured.
     improv_serial:
 
 
-No configuration variables.
+Configuration variables
+-----------------------
+
+- **next_url** (*Optional*, url): A URL that can be used to forward the user to after setting credentials with improv.
+
+Next URL
+--------
+
+Substitutions can be inserted into the URL, such as project name and version and there are some special substitutions
+that can be performed by ESPHome when wrapped in double braces ``{{ }}``:
+
+- **device_name**: This will substitute the device name including the mac address suffix.
+- **ip_address**: This will substitute the IP address of the device.
+- **esphome_version**: This will substitute the version of ESPHome that is running on the device.
+
+.. code-block:: yaml
+
+    # Example next_url
+    improv_serial:
+      next_url: http://example.com/?device_name={{device_name}}&ip_address={{ip_address}}&esphome_version={{esphome_version}}
 
 See Also
 --------

guides/creators.rst

@@ -61,6 +61,7 @@ Example configuration
 
     # Sets up the improv via serial client for Wi-Fi provisioning
     improv_serial:
+      next_url: https://example.com/project-template/manual?ip={{ip_address}}&name={{device_name}}&version={{esphome_version}}
 
 
 Relevant Documentation