Add list of related projects

Author: wooorm

readme.md

@@ -60,6 +60,39 @@ This project has a [code of conduct][coc].
 By interacting with this repository, organization, or community you agree to
 abide by its terms.
 
+## Related
+
+*   [`hast-util-is-element`](https://github.com/syntax-tree/hast-util-is-element)
+    — check if a node is a (certain) element
+*   [`hast-util-has-property`](https://github.com/syntax-tree/hast-util-has-property)
+    — check if a node has a property
+*   [`hast-util-is-body-ok-link`](https://github.com/rehypejs/rehype-minify/tree/master/packages/hast-util-is-body-ok-link)
+    — check if a node is “Body OK” link element
+*   [`hast-util-is-conditional-comment`](https://github.com/rehypejs/rehype-minify/tree/master/packages/hast-util-is-conditional-comment)
+    — check if a node is a conditional comment
+*   [`hast-util-is-css-link`](https://github.com/rehypejs/rehype-minify/tree/master/packages/hast-util-is-css-link)
+    — check if a node is a CSS link element
+*   [`hast-util-is-css-style`](https://github.com/rehypejs/rehype-minify/tree/master/packages/hast-util-is-css-style)
+    — check if a node is a CSS style element
+*   [`hast-util-embedded`](https://github.com/syntax-tree/hast-util-embedded)
+    — check if a node is an embedded element
+*   [`hast-util-heading`](https://github.com/syntax-tree/hast-util-heading)
+    — check if a node is a heading element
+*   [`hast-util-interactive`](https://github.com/syntax-tree/hast-util-interactive)
+    — check if a node is interactive
+*   [`hast-util-is-javascript`](https://github.com/rehypejs/rehype-minify/tree/master/packages/hast-util-is-javascript)
+    — check if a node is a JavaScript script element
+*   [`hast-util-labelable`](https://github.com/syntax-tree/hast-util-labelable)
+    — check whether a node is labelable
+*   [`hast-util-phrasing`](https://github.com/syntax-tree/hast-util-phrasing)
+    — check if a node is phrasing content
+*   [`hast-util-script-supporting`](https://github.com/syntax-tree/hast-util-script-supporting)
+    — check if a node is a script-supporting element
+*   [`hast-util-transparent`](https://github.com/syntax-tree/hast-util-transparent)
+    — check if a node is a transparent element
+*   [`hast-util-whitespace`](https://github.com/syntax-tree/hast-util-whitespace)
+    — check if a node is inter-element whitespace
+
 ## Security
 
 `hast-util-sectioning` does not change the syntax tree so there are no openings