Refactor docs

Author: wooorm

readme.md

@@ -69,7 +69,7 @@ If your content is not in English, you should configure that utility.
 ## 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-gfm-footnote
@@ -256,7 +256,7 @@ FootnoteReference includes Association
 association.
 
 **FootnoteReference** can be used where
-**[static phrasing][dfn-static-phrasing-content]** content is expected.
+**[phrasing][dfn-phrasing-content]** content is expected.
 It has no content model.
 
 **FootnoteReference** includes the mixin **[Association][dfn-mxn-association]**.
@@ -288,10 +288,10 @@ Yields:
 type FlowContentGfm = FootnoteDefinition | FlowContent
 ```
 
-#### `StaticPhrasingContent` (GFM footnotes)
+#### `PhrasingContent` (GFM footnotes)
 
 ```idl
-type StaticPhrasingContentGfm = FootnoteReference | StaticPhrasingContent
+type PhrasingContentGfm = FootnoteReference | PhrasingContent
 ```
 
 ## Types
@@ -304,13 +304,13 @@ exposed from `@types/mdast`.
 
 ## 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.
 
-This plugin works with `mdast-util-from-markdown` version 1+ and
-`mdast-util-to-markdown` version 1+.
+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-gfm-footnote@^1`, compatible with Node.js 12.
 
 ## Related
 
@@ -350,9 +350,9 @@ abide by its terms.
 
 [downloads]: https://www.npmjs.com/package/mdast-util-gfm-footnote
 
-[size-badge]: https://img.shields.io/bundlephobia/minzip/mdast-util-gfm-footnote.svg
+[size-badge]: https://img.shields.io/badge/dynamic/json?label=minzipped%20size&query=$.size.compressedSize&url=https://deno.bundlejs.com/?q=mdast-util-gfm-footnote
 
-[size]: https://bundlephobia.com/result?p=mdast-util-gfm-footnote
+[size]: https://bundlejs.com/?q=mdast-util-gfm-footnote
 
 [sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg
 
@@ -420,7 +420,7 @@ abide by its terms.
 
 [dfn-flow-content]: #flowcontent-gfm-footnotes
 
-[dfn-static-phrasing-content]: #staticphrasingcontent-gfm-footnotes
+[dfn-phrasing-content]: #phrasingcontent-gfm-footnotes
 
 [dfn-footnote-reference]: #footnotereference