Support values property in MessageDescriptor.

README.md

@@ -201,6 +201,15 @@ We can also add a comment for the translators reading the message catalog e.g. t
 })}
 ```
 
+Also, if you need to interpolate dynamic values into the message, you can use the `values` property in the MessageDescriptor object:
+
+```svelte
+{$t({
+	message: 'Hello {name}!',
+	values: { name: 'World' }
+})}
+```
+
 ### Plurals
 
 To provide different messages for text with numbers, use the provided `$plural` store:

src/lib/index.js

@@ -4,6 +4,7 @@
  * @property {string} message - The message to be translated.
  * @property {string} [context] - The context of the message, will be included in the po file. The same message with different context will be extracted as separate entries, and can be translated differently.
  * @property {string} [comment] - A comment purely for giving information to the translator, won't affect translated string.
+ * @property {Record<string, any>} [values] - An optional dictionary of values to be used in the message.
  */
 
 import { writable, derived } from 'svelte/store';