Fix references to the renamed 'auxiliary' directory.

I renamed it in a hurry this morning after the first report of a git
error message on Windows. Now I realise that several source files
referred to the old name, and also need fixing.

auxiliary/hatgen-images.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 
-# Regenerate all the SVG images in the aux/doc directory for hats.html
-# and hatmap.html.
+# Regenerate all the SVG images in the auxiliary/doc directory for
+# hats.html and hatmap.html.
 
 set -e
 

auxiliary/hatgen.c

@@ -1459,7 +1459,7 @@ int main(int argc, char **argv)
         size_t i, j, k;
 
         printf("/*\n"
-               " * Header file autogenerated by aux/hatgen.c\n"
+               " * Header file autogenerated by auxiliary/hatgen.c\n"
                " *\n"
                " * To regenerate, run 'hatgen --tables > hat-tables.h'\n"
                " */\n\n");

hat-tables.h

@@ -1,5 +1,5 @@
 /*
- * Header file autogenerated by aux/hatgen.c
+ * Header file autogenerated by auxiliary/hatgen.c
  *
  * To regenerate, run 'hatgen --tables > hat-tables.h'
  */

hat.c

@@ -2,10 +2,10 @@
  * Code to generate patches of the aperiodic 'hat' tiling discovered
  * in 2023.
  *
- * aux/doc/hats.html contains an explanation of the basic ideas of
- * this algorithm, which can't really be put in a source file because
- * it just has too many complicated diagrams. So read that first,
- * because the comments in here will refer to it.
+ * auxiliary/doc/hats.html contains an explanation of the basic ideas
+ * of this algorithm, which can't really be put in a source file
+ * because it just has too many complicated diagrams. So read that
+ * first, because the comments in here will refer to it.
  *
  * Discoverers' website: https://cs.uwaterloo.ca/~csk/hat/
  * Preprint of paper:    https://arxiv.org/abs/2303.10798