tests: Add test for rotated annotation

tests/plot/annotation/test.typ

@@ -23,3 +23,24 @@
     })
   })
 })
+
+#test-case({
+  import draw: *
+  set-style(rect: (stroke: none))
+
+  plot.plot(size: (6, 4), x-horizontal: false, y-horizontal: true, {
+    plot.add(domain: (-calc.pi, 3*calc.pi), calc.sin)
+    plot.annotate(background: true, {
+      rect((0, -1),       (calc.pi, 1), fill: blue.lighten(90%))
+      rect((calc.pi, -1.1), (2*calc.pi, 1.1), fill: red.lighten(90%))
+      rect((2*calc.pi, -1.5), (3.5*calc.pi, 1.5), fill: green.lighten(90%))
+    })
+    plot.annotate(padding: .1, {
+      line((calc.pi / 2, 1.1), (rel: (0, .2)), (rel: (2*calc.pi, 0)), (rel: (0, -.2)))
+      content((calc.pi * 1.5, 1.5), $ lambda $)
+    })
+    plot.annotate(padding: .1, {
+      line((calc.pi / 2,-.1), (calc.pi / 2, .8), mark: (end: "stealth"))
+    })
+  })
+})