add customchords in book test

test/test_book/syntax.tex.control

@@ -90,6 +90,25 @@ guitar,
 \addcontentsline{toc}{section}{\songlistname}
 
 \begin{songs}{titleidx,authidx}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% songs/./customchords.csg
+
+\selectlanguage{english}
+
+\beginsong{}[
+  by={
+  },
+]
+
+\gtab{E4}{7:0133XX}
+\gtab{E5}{7:0133XX:012300}
+\gtab{E5/A*}{7:0133XX:012300}
+\gtab{A#+2}{7:0133XX:012300}
+\utab{A}{2100}
+
+
+\endsong
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% songs/./images.csg
 

test/test_book/syntax_datadir/songs/customchords.csg

@@ -0,0 +1,6 @@
+{lang: en}
+{define: E4 base-fret 7 frets 0 1 3 3 x x}
+{define: E5 base-fret 7 frets 0 1 3 3 x x fingers - 1 2 3 - -}
+{define: E5/A* base-fret 7 frets 0 1 3 3 x x fingers - 1 2 3 - -}
+{define: A#+2 base-fret 7 frets 0 1 3 3 x x fingers - 1 2 3 - -}
+{define: A frets 2 1 0 0}