[Docs] Update links that should point to Vercel repos (vercel#15547)

From feedback, we still have some links that go to zeit repos instead of vercel

docs/api-reference/next.config.js/custom-webpack-config.md

@@ -15,7 +15,7 @@ Before continuing to add custom webpack configuration to your application make s
 
 Some commonly asked for features are available as plugins:
 
-- [@zeit/next-less](https://github.com/zeit/next-plugins/tree/master/packages/next-less)
+- [@zeit/next-less](https://github.com/vercel/next-plugins/tree/master/packages/next-less)
 - [@next/mdx](https://github.com/vercel/next.js/tree/canary/packages/next-mdx)
 - [@next/bundle-analyzer](https://github.com/vercel/next.js/tree/canary/packages/next-bundle-analyzer)
 

docs/basic-features/built-in-css-support.md

@@ -129,8 +129,8 @@ module.exports = {
 
 To support importing `.less` or `.styl` files you can use the following plugins:
 
-- [@zeit/next-less](https://github.com/zeit/next-plugins/tree/master/packages/next-less)
-- [@zeit/next-stylus](https://github.com/zeit/next-plugins/tree/master/packages/next-stylus)
+- [@zeit/next-less](https://github.com/vercel/next-plugins/tree/master/packages/next-less)
+- [@zeit/next-stylus](https://github.com/vercel/next-plugins/tree/master/packages/next-stylus)
 
 If using the less plugin, don't forget to add a dependency on less as well, otherwise you'll see an error like:
 
@@ -164,7 +164,7 @@ function HiThere() {
 export default HiThere
 ```
 
-We bundle [styled-jsx](https://github.com/zeit/styled-jsx) to provide support for isolated scoped CSS.
+We bundle [styled-jsx](https://github.com/vercel/styled-jsx) to provide support for isolated scoped CSS.
 The aim is to support "shadow CSS" similar to Web Components, which unfortunately [do not support server-rendering and are JS-only](https://github.com/w3c/webcomponents/issues/71).
 
 See the above examples for other popular CSS-in-JS solutions (like Styled Components).
@@ -202,7 +202,7 @@ function HelloWorld() {
 export default HelloWorld
 ```
 
-Please see the [styled-jsx documentation](https://github.com/zeit/styled-jsx) for more examples.
+Please see the [styled-jsx documentation](https://github.com/vercel/styled-jsx) for more examples.
 
 ## FAQ
 

docs/routing/dynamic-routes.md

@@ -99,7 +99,7 @@ The `query` objects are as follows:
 { "slug": ["a", "b"] } // `GET /post/a/b` (multi-element array)
 ```
 
-> A good example of optional catch all routes is the Next.js docs, a single page called [pages/docs/[[...slug]].js](https://github.com/zeit/next-site/blob/master/pages/docs/%5B%5B...slug%5D%5D.js) takes care of all the docs you're currently looking at.
+> A good example of optional catch all routes is the Next.js docs, a single page called [pages/docs/[[...slug]].js](https://github.com/vercel/next-site/blob/master/pages/docs/%5B%5B...slug%5D%5D.js) takes care of all the docs you're currently looking at.
 
 ## Caveats
 

docs/upgrading.md

@@ -104,7 +104,7 @@ Next.js now has the concept of page-level configuration, so the `withAmp` higher
 This change can be **automatically migrated by running the following commands in the root of your Next.js project:**
 
 ```bash
-curl -L https://github.com/zeit/next-codemod/archive/master.tar.gz | tar -xz --strip=2 next-codemod-master/transforms/withamp-to-config.js npx jscodeshift -t ./withamp-to-config.js pages/**/*.js
+curl -L https://github.com/vercel/next-codemod/archive/master.tar.gz | tar -xz --strip=2 next-codemod-master/transforms/withamp-to-config.js npx jscodeshift -t ./withamp-to-config.js pages/**/*.js
 ```
 
 To perform this migration by hand, or view what the codemod will produce, see below: