Add improved docs

Author: wooorm

readme.md

@@ -38,7 +38,7 @@ looking for!
 ## Install
 
 This package is [ESM only][esm].
-In Node.js (version 12.20+, 14.14+, 16.0+, or 18.0+), install with [npm][]:
+In Node.js (version 14.14+ and 16.0+), install with [npm][]:
 
 ```sh
 npm install hast-util-whitespace
@@ -82,7 +82,7 @@ whitespace({
 
 ## API
 
-This package exports the identifier `whitespace`.
+This package exports the identifier [`whitespace`][whitespace].
 There is no default export.
 
 ### `whitespace(thing)`
@@ -111,7 +111,7 @@ It exports no additional types.
 
 Projects maintained by the unified collective are compatible with all maintained
 versions of Node.js.
-As of now, that is Node.js 12.20+, 14.14+, 16.0+, and 18.0+.
+As of now, that is Node.js 14.14+ and 16.0+.
 Our projects sometimes work with older versions, but this is not guaranteed.
 
 ## Security
@@ -223,3 +223,5 @@ abide by its terms.
 [text]: https://github.com/syntax-tree/hast#text
 
 [xss]: https://en.wikipedia.org/wiki/Cross-site_scripting
+
+[whitespace]: #whitespacething