Update example for I18N custom keys (#2117)

Signed-off-by: Jacob Laursen <jacob-github@vindvejr.dk>

developers/utils/i18n.md

@@ -408,29 +408,40 @@ The keys are unique across the whole bundle, so a constant can reference any key
 
 The following snippet shows a binding XML that uses custom keys:
 
-XML file (`binding.xml`):
+XML file (`addon.xml`):
 
 ```xml
-<binding:binding id="acmeweather">
-    <name>@text/bindingName</name>
-    <description>@text/bindingName</description>
-</binding:binding>
+<addon:addon id="acmeweather">
+    <type>binding</type>
+    <name>@text/addon.acmeweather.name</name>
+    <description>@text/addon.acmeweather.description</description>
+</addon:addon>
 ```
 
 Language file (`acmeweather_en.properties`):
 
 ```ini
-bindingName = ACME Weather Binding
+# add-on
+
+addon.acmeweather.name = ACME Weather Binding
+addon.acmeweather.description = Binding for ACME Weather
 
-offline.communication-error=The ACME Weather API is currently not available.
+# thing status descriptions
+
+offline.communication-error = The ACME Weather API is currently not available.
 ```
 
 Language file (`acmeweather_de.properties`):
 
 ```ini
-bindingName = ACME Wetter Binding
+# add-on
+
+addon.acmeweather.name = ACME Wetter Binding
+addon.acmeweather.description = Binding für ACME Wetter
+
+# thing status descriptions
 
-offline.communication-error=Die ACME Wetter API ist zur Zeit nicht verfügbar.
+offline.communication-error = Die ACME Wetter API ist zur Zeit nicht verfügbar.
 ```
 
 The custom keys are a very good practice to translate bundle dependent error messages.