[USE] Start moving Unicode-to-USE mapping into Python code

src/hb-ot-shape-complex-use-table.cc

diff --git a/src/hb-ot-shape-complex-use-table.cc b/src/hb-ot-shape-complex-use-table.cc
index 0ca4cc4..8f5234c 100644
--- a/src/hb-ot-shape-complex-use-table.cc
+++ b/src/hb-ot-shape-complex-use-table.cc
@@ -2,7 +2,7 @@
 /*
  * The following table is generated by running:
  *
- *   ./gen-use-table.py IndicSyllabicCategory.txt IndicPositionalCategory.txt Blocks.txt
+ *   ./gen-use-table.py IndicSyllabicCategory.txt IndicPositionalCategory.txt UnicodeData.txt Blocks.txt
  *
  * on files with these headers:
  *
@@ -12,6 +12,7 @@
  * # Date: 2015-05-12, 10:00:00 GMT [RP, KW, LI]
  * # Blocks-8.0.0.txt
  * # Date: 2014-11-10, 23:04:00 GMT [KW]
+ * UnicodeData.txt does not have a header.
  */
 
 #include "hb-ot-shape-complex-use-private.hh"