Move URL out of Mastodon strings.json (home-assistant#154231)

Author: andrew-codechimp

homeassistant/components/mastodon/config_flow.py

@@ -134,4 +134,8 @@ async def async_step_user(
                     data=user_input,
                 )
 
-        return self.show_user_form(user_input, errors)
+        return self.show_user_form(
+            user_input,
+            errors,
+            description_placeholders={"example_url": "https://mastodon.social"},
+        )

homeassistant/components/mastodon/strings.json

@@ -9,7 +9,7 @@
           "access_token": "[%key:common::config_flow::data::access_token%]"
         },
         "data_description": {
-          "base_url": "The URL of your Mastodon instance e.g. https://mastodon.social.",
+          "base_url": "The URL of your Mastodon instance e.g. {example_url}.",
           "client_id": "The client key for the application created within your Mastodon account.",
           "client_secret": "The client secret for the application created within your Mastodon account.",
           "access_token": "The access token for the application created within your Mastodon account."