Remove old base styles page

We were already redirecting from this to a new page but the page still existed if you navigated to it with a client-side visit.

Author: adamwathan

src/pages/docs/adding-base-styles.mdx

@@ -73,7 +73,7 @@ The reason for this is two-fold:
 - **It helps you avoid accidentally deviating from your type scale**. By default, browsers assign sizes to headings that don't exist in Tailwind's default type scale, and aren't guaranteed to exist in your own type scale.
 - **In UI development, headings should often be visually de-emphasized**. Making headings unstyled by default means any styling you apply to headings happens consciously and deliberately.
 
-You can always add default header styles to your project by [adding your own base styles](/docs/adding-base-styles).
+You can always add default header styles to your project by [adding your own base styles](/docs/adding-custom-styles#adding-base-styles).
 
 If you'd like to selectively introduce sensible default heading styles into article-style parts of a page, we recommend the [@tailwindcss/typography plugin](/docs/typography-plugin/).
 
@@ -102,7 +102,7 @@ If you'd like to style a list, you can do so using the [list-style-type](/docs/l
 </ul>
 ```
 
-You can always add default list styles to your project by [adding your own base styles](/docs/adding-base-styles).
+You can always add default list styles to your project by [adding your own base styles](/docs/adding-custom-styles#adding-base-styles).
 
 If you'd like to selectively introduce default list styles into article-style parts of a page, we recommend the [@tailwindcss/typography plugin](/docs/typography-plugin/).
 
@@ -223,7 +223,7 @@ If you'd like to add your own base styles on top of Preflight, simply add them t
 @tailwind utilities;
 ```
 
-Learn more in the [adding base styles documentation](/docs/adding-base-styles).
+Learn more in the [adding base styles documentation](/docs/adding-custom-styles#adding-base-styles).
 
 ---