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/path/split/readme.mdx

@@ -0,0 +1,69 @@
+---
+title: Path.split()
+---
+
+The `Path.split()` method splits a path in two halves, on a point along that
+path that you pass it.
+
+## Signature
+
+```js
+array path.split(Point splitPoint)
+```
+
+## Example
+
+<Example caption="Example of the Path.split() method">
+```js
+({ Point, points, Path, paths, snippets, Snippet, part }) => {
+
+  points.A = new Point(45, 60)
+  points.B = new Point(10, 30)
+  points.BCp2 = new Point(40, 20)
+  points.C = new Point(90, 30)
+  points.CCp1 = new Point(50, -30)
+  points.D = new Point(50, 130)
+  points.DCp1 = new Point(150, 30)
+
+  paths.demo = new Path()
+    .move(points.D)
+    .curve(points.DCp1, points.DCp1, points.C)
+    .curve(points.CCp1, points.BCp2, points.B)
+    .line(points.A)
+
+  points.split = paths.demo.shiftFractionAlong(0.75)
+  snippets.split = new Snippet("notch", points.split)
+
+  let halves = paths.demo.split(points.split)
+  for (let i in halves) {
+    paths[i] = halves[i]
+      .attr("style", "stroke-width: 3; stroke-opacity: 0.5;")
+      .attr("style", `stroke: hsl(${i * 70}, 100%, 50%)`)
+  }
+
+  return part
+}
+```
+</Example>
+
+## Notes
+
+### The returned array will hold null for edge cases
+
+Typically, the returned array will hold a `Path` object for each half.
+But in some cases, one of the array entries can hold `null` if the split failed to find a path.
+For example because you are splitting a `Path` on its start or end point.
+
+```mjs
+// Return value for a normal case
+[Path, Path]
+// Return value when calling Path.split() on/near the path's start point
+[null, Path]
+// Return value when calling Path.split() on/near the path's end point
+[Path, null]
+```
+
+### This method will snap the split point to start or end points
+This method will also _snap_ to the start or end point if you are splitting a path
+(very) close to it, as it checks with [`Point.sitsRoughlyOn()`](/reference/api/point/sitsroughlyon).
+