Add (see man synctex) to luainit.w

[[Split portion of a mixed commit.]]

source/texk/web2c/luatexdir/lua/luainit.w

@@ -91,7 +91,7 @@ const_string LUATEX_IHELP[] = {
     "   --safer                       disable easily exploitable lua commands",
     "   --[no-]shell-escape           disable/enable system commands",
     "   --shell-restricted            restrict system commands to a list of commands given in texmf.cnf",
-    "   --synctex=NUMBER              enable synctex",
+    "   --synctex=NUMBER              enable synctex (see man synctex)",
     "   --utc                         init time to UTC",
     "   --version                     display version and exit",
     "",