docs(v11): migration note for hidden mixin (#10933)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

docs/migration/v11.md

@@ -334,7 +334,7 @@ that details to which files a particular helper has been moved.
 | `@mixin box-shadow`         | `scss/utilities/_box-shadow.scss`         |
 | `@mixin focus-outline`      | `scss/utilities/_focus-outline.scss`      |
 | `@mixin rotate`             | `scss/utilities/_rotate.scss`             |
-| `@mixin hidden`             | TODO                                      |
+| `@mixin hidden`             | `scss/utilities/_visually-hidden.scss`    |
 | `@mixin button-reset`       | `scss/utilities/_button-reset.scss`       |
 | `@mixin skeleton`           | `scss/utilities/_skeleton.scss`           |
 | `@keyframes skeleton`       | `scss/utilities/_keyframes.scss` TODO     |