feat: Flat import of markdown repo

This is a flat (without history) import of (some of) the content
from our markdown module.

We've imported this without history because the repo contains our
blog posts and showcases posts content prior to porting them to strapi.

Since this contains many images, it would balloon the size of this repo
to import the full history.

Instead, please refer to the history of the (archived) markdown repo
at: https://github.com/freesewing/markdown

markdown/dev/reference/api/utils/pointoncurve/en.md

@@ -0,0 +1,67 @@
+---
+title: pointOnCurve()
+---
+
+```js
+bool utils.pointOnCurve(
+  Point start, 
+  Point cp1, 
+  Point cp2, 
+  Point end, 
+  Point check
+)
+```
+
+Returns `true` if the point `check` lies on a curve described by points `start`, `cp1`, `cp2`, and `end`.
+
+<Note>
+
+Keep in mind that calculations with Bezier curves are often aproximations.
+
+</Note>
+
+<Example part="utils_pointoncurve" caption="A Utils.pointOnCurve() example" />
+
+```js
+let {
+  Point,
+  points,
+  Path,
+  paths,
+  Snippet,
+  snippets,
+  utils
+} = part.shorthand();
+
+points.start = new Point(10, 10);
+points.cp1 = new Point(90, 10);
+points.cp2 = new Point(10, 60);
+points.end = new Point(90, 60);
+
+let scatter = [];
+for (let i = 1; i < 19; i++) {
+  for (let j = 1; j < 14; j++) {
+    scatter.push(new Point(i * 10, j * 10));
+  }
+}
+let snippet;
+for (let point of scatter) {
+  if (
+    utils.pointOnCurve(
+      points.start,
+      points.cp1,
+      points.cp2,
+      points.end,
+      point
+    )
+  ) {
+    snippet = "notch";
+  } else snippet = "bnotch";
+  snippets[part.getId()] = new Snippet(snippet, point);
+}
+paths.curve = new Path()
+  .move(points.start)
+  .curve(points.cp1, points.cp2, points.end)
+  .attr("class", "fabric stroke-lg");
+```
+