Refactor docs

Author: wooorm

readme.md

@@ -45,7 +45,7 @@ for any [unist][] node.
 ## Install
 
 This package is [ESM only][esm].
-In Node.js (version 14.14+ and 16.0+), install with [npm][]:
+In Node.js (version 16+), install with [npm][]:
 
 ```sh
 npm install mdast-util-assert
@@ -111,7 +111,7 @@ Nothing.
 ###### Throws
 
 When `tree` (or its descendants) is not an mdast node
-([`AssertionError`][assertionerror]).
+([`AssertionError`][api-assertion-error]).
 
 ### `parent(tree[, parent])`
 
@@ -135,7 +135,7 @@ Nothing.
 ###### Throws
 
 When `tree` is not a parent or its descendants are not nodes
-([`AssertionError`][assertionerror])
+([`AssertionError`][api-assertion-error])
 
 ### `literal(node[, parent])`
 
@@ -156,7 +156,7 @@ Nothing.
 
 ###### Throws
 
-When `node` is not an mdast literal ([`AssertionError`][assertionerror]).
+When `node` is not an mdast literal ([`AssertionError`][api-assertion-error]).
 
 ### `_void(node[, parent])`
 
@@ -173,14 +173,17 @@ Re-exported from [`unist-util-assert`][unist-util-assert-assertionerror].
 ## Types
 
 This package is fully typed with [TypeScript][].
-It exports the additional type [`AssertionError`][assertionerror].
+It exports the additional type [`AssertionError`][api-assertion-error].
 
 ## Compatibility
 
-Projects maintained by the unified collective are compatible with all maintained
+Projects maintained by the unified collective are compatible with maintained
 versions of Node.js.
-As of now, that is Node.js 14.14+ and 16.0+.
-Our projects sometimes work with older versions, but this is not guaranteed.
+
+When we cut a new major release, we drop support for unmaintained versions of
+Node.
+This means we try to keep the current release line, `mdast-util-assert@^4`,
+compatible with Node.js 12.
 
 ## Security
 
@@ -224,9 +227,9 @@ abide by its terms.
 
 [downloads]: https://www.npmjs.com/package/mdast-util-assert
 
-[size-badge]: https://img.shields.io/bundlephobia/minzip/mdast-util-assert.svg
+[size-badge]: https://img.shields.io/badge/dynamic/json?label=minzipped%20size&query=$.size.compressedSize&url=https://deno.bundlejs.com/?q=mdast-util-assert
 
-[size]: https://bundlephobia.com/result?p=mdast-util-assert
+[size]: https://bundlejs.com/?q=mdast-util-assert
 
 [sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg
 
@@ -284,7 +287,7 @@ abide by its terms.
 
 [api-wrap]: #wrapfn
 
-[assertionerror]: #assertionerror
+[api-assertion-error]: #assertionerror
 
 [unist-util-assert-void]: https://github.com/syntax-tree/unist-util-assert#_voidnode-parent