Bump @shikijs/vitepress-twoslash from 3.15.0 to 3.20.0 (#1003)

Bumps
[@shikijs/vitepress-twoslash](https://github.com/shikijs/shiki/tree/HEAD/packages/vitepress-twoslash)
from 3.15.0 to 3.20.0.

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/package.json

@@ -25,7 +25,7 @@
     "medium-zoom": "^1.1.0"
   },
   "devDependencies": {
-    "@shikijs/vitepress-twoslash": "^3.15.0",
+    "@shikijs/vitepress-twoslash": "^3.20.0",
     "vitepress": "^2.0.0-alpha.15",
     "vitepress-plugin-group-icons": "^1.6.5"
   }