Add regression test for #541.

I broke the rendering of diacritics a couple of weeks ago, so we
definitely need a regression test for this issue.

The version number is correct, since it was backported to 2.12.3.

diff --git a/input/regression/markup-diacritic-marks.ly b/input/regression/markup-diacritic-marks.ly
new file mode 100644 (file)
index 0000000..e56a82b
--- /dev/null
+++ b/input/regression/markup-diacritic-marks.ly
@@ -0,0 +1,19 @@
+\version "2.12.3"
+
+\header {
+  texidoc = "
+Diacritic marks are rendered and positioned correctly.  The
+diacritic on line 1 looks like a lower-underline and is centered
+beneath the main character.  The diacritic on line 2 is positioned
+to the left of the main character, with a tiny space of
+separation.  The diacritic on line 3 is positioned directly above
+the main character, either centered or shifted slightly to the
+left.
+"
+}
+
+\markup {
+  \column {
+    כַ וּ וֹ
+  }
+}