Make the function signature less prominent, add an early example to docs

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

docs/kcl-std/functions/std-sketch-lastSegY.md

@@ -8,11 +8,18 @@ layout: manual
 Extract the 'y' axis value of the last line segment in the provided 2-d sketch.
 
 ```kcl
-lastSegY(@sketch: Sketch): number(Length)
+exampleSketch = startSketchOn(XZ)
+  |> startProfile(at = [0, 0])
+  |> line(end = [5, 0])
+  |> line(end = [20, 5])
+  |> line(end = [0, lastSegY(%)])
+  |> line(end = [-15, 0])
+  |> close()
+
+example = extrude(exampleSketch, length = 5)
+
 ```
 
-
-
 ### Arguments
 
 | Name | Type | Description | Required |
@@ -24,6 +31,12 @@ lastSegY(@sketch: Sketch): number(Length)
 [`number(Length)`](/docs/kcl-std/types/std-types-number) - A number.
 
 
+### Function signature
+
+```kcl
+lastSegY(@sketch: Sketch): number(Length)
+```
+
 ### Examples
 
 ```kcl