feat(toast-notification): make title/subtitle/caption slottable

docs/src/COMPONENT_API.json

@@ -12279,7 +12279,27 @@
           "reactive": false
         }
       ],
-      "slots": [{ "name": "__default__", "default": true, "slot_props": "{}" }],
+      "slots": [
+        { "name": "__default__", "default": true, "slot_props": "{}" },
+        {
+          "name": "caption",
+          "default": false,
+          "fallback": "{caption}",
+          "slot_props": "{}"
+        },
+        {
+          "name": "subtitle",
+          "default": false,
+          "fallback": "{subtitle}",
+          "slot_props": "{}"
+        },
+        {
+          "name": "title",
+          "default": false,
+          "fallback": "{title}",
+          "slot_props": "{}"
+        }
+      ],
       "events": [
         {
           "type": "dispatched",

docs/src/pages/components/ToastNotification.svx

@@ -11,6 +11,14 @@ source: Notification/ToastNotification.svelte
 
 <ToastNotification title="Error" subtitle="An internal server error occurred." caption="{new Date().toLocaleString()}" />
 
+### Slottable title, subtitle, caption
+
+<ToastNotification>
+  <strong slot="title">Error: </strong>
+  <strong slot="subtitle">An internal server error occurred.</strong>
+  <strong slot="caption">{new Date().toLocaleString()}</strong>
+</ToastNotification>
+
 ### Hidden close button
 
 <ToastNotification hideCloseButton kind="warning" title="Scheduled maintenance" subtitle="Maintenance will last 2-4 hours." caption="{new Date().toLocaleString()}" />