docs: describe that `bind:value` creates a two-way binding (#8311)

---------

Co-authored-by: Simon H <5968653+dummdidumm@users.noreply.github.com>

site/content/tutorial/06-bindings/05-textarea-inputs/text.md

@@ -1,8 +1,7 @@
 ---
 title: Textarea inputs
 ---
-
-The `<textarea>` element behaves similarly to a text input in Svelte — use `bind:value`:
+The `<textarea>` element behaves similarly to a text input in Svelte — use `bind:value` to create a two-way binding between the `<textarea>` content and the `value` variable:
 
 ```html
 <textarea bind:value={value}></textarea>
@@ -14,4 +13,4 @@ In cases like these, where the names match, we can also use a shorthand form:
 <textarea bind:value></textarea>
 ```
 
-This applies to all bindings, not just textareas.
+This applies to all bindings, not just textareas.