ThemeAttributes: add data-author-username to messages (#2422)

src/plugins/themeAttributes/README.md

@@ -15,6 +15,7 @@ This allows themes to more easily theme those elements or even do things that ot
 ### Chat Messages
 
 - `data-author-id` contains the id of the author
+- `data-author-username` contains the username of the author
 - `data-is-self` is a boolean indicating whether this is the current user's message
 
 ![image](https://github.com/Vendicated/Vencord/assets/45497981/34bd5053-3381-402f-82b2-9c812cc7e122)

src/plugins/themeAttributes/index.ts

@@ -36,10 +36,12 @@ export default definePlugin({
     ],
 
     getMessageProps(props: { message: Message; }) {
-        const authorId = props.message?.author?.id;
+        const author = props.message?.author;
+        const authorId = author?.id;
         return {
             "data-author-id": authorId,
-            "data-is-self": authorId && authorId === UserStore.getCurrentUser()?.id
+            "data-author-username": author?.username,
+            "data-is-self": authorId && authorId === UserStore.getCurrentUser()?.id,
         };
     }
 });