docs: "generateMetadata" to "generateViewport" in doc "generateViewpo…

…rt" (#64795)

Changed "generateMetadata" to "generateViewport" in
generate-viewport.mdx

Co-authored-by: Sam Ko <sam@vercel.com>

docs/02-app/02-api-reference/04-functions/generate-viewport.mdx

@@ -61,7 +61,7 @@ export function generateViewport({ params }) {
 
 > **Good to know**:
 >
-> - If the viewport doesn't depend on runtime information, it should be defined using the static [`viewport` object](#the-viewport-object) rather than `generateMetadata`.
+> - If the viewport doesn't depend on runtime information, it should be defined using the static [`viewport` object](#the-viewport-object) rather than `generateViewport`.
 
 ## Viewport Fields