Update coinbase.markdown with new docs (#7412)

* Update coinbase.markdown

Delete trailing spaces
Keep example configuration minimal
Add new `account_balance_currencies` option

* Added a full configuration example

source/_components/coinbase.markdown

@@ -13,7 +13,6 @@ ha_release: 0.61
 ha_iot_class: "Cloud Polling"
 ---
 
-
 The `coinbase` component lets you access account balances and exchange rates from [coinbase](https://coinbase.com).
 
 You will need to obtain an API key from coinbase's [developer site](https://www.coinbase.com/settings/api) to use this component. You need to give read access to `wallet:accounts` in order for the component to access relevant data. 
@@ -25,12 +24,8 @@ To set it up, add the following information to your `configuration.yaml` file:
 ```yaml
 # Example configuration.yaml entry
 coinbase:
-  api_key: YOUR_API_KEY 
-  api_secret: YOUR_API_SECRET 
-  exchange_rate_currencies:
-    - BTC
-    - ETH
-    - LTC
+  api_key: YOUR_API_KEY
+  api_secret: YOUR_API_SECRET
 ```
 
 {% configuration %}
@@ -42,8 +37,33 @@ api_secret:
   description: Your API secret to access coinbase.
   required: true
   type: string
+account_balance_currencies:
+  description: List of currencies to create account wallet sensors for.
+  required: false
+  type: list
+  default: all account wallets
 exchange_rate_currencies:
   description: List of currencies to create exchange rate sensors for.
   required: false
   type: list
 {% endconfiguration %}
+
+Possible currencies are codes that conform to the ISO 4217 standard where possible. Currencies which have or had no representation in ISO 4217 may use a custom code (e.g. BTC). A list of values can be obtained via https://api.coinbase.com/v2/currencies, for more information visit [the Coinbase API documentation](https://developers.coinbase.com/api/v2#get-currencies).
+
+## {% linkable_title Full configuration example %}
+
+A full configuration sample including optional variables:
+
+```yaml
+# Example configuration.yaml entry
+coinbase:
+  api_key: YOUR_API_KEY
+  api_secret: YOUR_API_SECRET
+  account_balance_currencies:
+    - EUR
+    - BTC
+  exchange_rate_currencies:
+    - BTC
+    - ETH
+    - LTC
+```