Support calling KCL std KW fns, and move circle to KCL std

Signed-off-by: Nick Cameron <nrc@ncameron.org>

rust/kcl-lib/std/sketch.kcl

@@ -0,0 +1,25 @@
+@no_std
+
+/// Construct a 2-dimensional circle, of the specified radius, centered at
+/// the provided (x, y) origin point.
+///
+/// ```
+/// exampleSketch = startSketchOn(-XZ)
+///   |> circle(center = [0, 0], radius = 10)
+///
+/// example = extrude(exampleSketch, length = 5)
+/// ```
+///
+/// ```
+/// exampleSketch = startSketchOn(XZ)
+///   |> startProfileAt([-15, 0], %)
+///   |> line(end = [30, 0])
+///   |> line(end = [0, 30])
+///   |> line(end = [-30, 0])
+///   |> close()
+///   |> hole(circle(center = [0, 15], radius = 5), %)
+///
+/// example = extrude(exampleSketch, length = 5)
+/// ```
+@(impl = std_rust)
+export fn circle(@sketch_or_surface: Sketch | Plane | Face, center: Point2d, radius: number, tag?: tag): Sketch {}