fix: add marked dependency for Part 1 / Bindings / Textarea inputs (sveltejs#175)

..by adding it as node_modules to app-a

Co-authored-by: Simon H <[email protected]>

Author: ivanbtrujillo

content/tutorial/01-svelte/06-bindings/05-textarea-inputs/README.md

@@ -2,8 +2,6 @@
 title: Textarea inputs
 ---
 
-> This exercise doesn't currently work. You can switch to the old tutorial instead: https://svelte.dev/tutorial/textarea-inputs
-
 The `<textarea>` element behaves similarly to a text input in Svelte — use `bind:value`:
 
 ```svelte