Explain the need for this test case

tests/test_workflow.py

@@ -73,6 +73,11 @@ async def processGlyph(self, glyph: VariableGlyph) -> VariableGlyph:
     ),
     (
         """
+# This test font contains two problem cases:
+# 1. VG_531A_00 contains a rectangle that has no width in a single source,
+#    which uncovered a bug with implied lineto calls with the CFF writer.
+# 2. uni3479 (㑹) which uses "asymmetrical" axes, that lead to wrong results
+#    in normalized space: https://github.com/googlefonts/fontra-compile/issues/45
 steps:
 - input: fontra-read
   source: "tests/data/notosanscjksc.fontra"