chore: Port FreeSewing.dev to docusaurus

The replaces the NextJS site powering FreeSewing.dev with a Docusaurus
setup. It's part of my efforts to simplify FreeSewing's setup so we can
focus on our core value proposition.

sites/dev/docs/reference/api/utils/linesintersect/readme.mdx

@@ -0,0 +1,43 @@
+---
+title: utils.linesIntersect()
+---
+
+The `utils.linesIntersect()` function finds the intersection between two line
+segments. Returns a [Point](/reference/api/point/) object for the intersection, or `false`
+if the lines don't intersect.
+
+## Signature
+
+```js
+Point | false utils.linesIntersect(
+  Point A,
+  Point B,
+  Point C,
+  Point D
+)
+```
+
+## Example
+
+<Example caption="A Utils.linesIntersect() example">
+```js
+({ Point, points, Path, paths, Snippet, snippets, utils, part }) => {
+
+  points.A = new Point(10, 10)
+  points.B = new Point(50, 40)
+  points.C = new Point(15, 30)
+  points.D = new Point(60, 15)
+
+  paths.AB = new Path().move(points.A).line(points.B)
+  paths.CD = new Path().move(points.C).line(points.D)
+
+  snippets.X = new Snippet(
+    "notch",
+    utils.linesIntersect(points.A, points.B, points.C, points.D)
+  )
+
+  return part
+}
+```
+</Example>
+