Update rule 6, and undo Index->Hyper

Author: eriknw

include/binsparse/c_bindings/binsparse_matrix.h

@@ -369,7 +369,7 @@ bc_type_code ;
 //      (..., Index, Hyper, ...) is not valid.
 //
 // (6) (..., Hyper, Sparse, ...) can be defined but is not useful.
-//      The same can be done with (..., Index, Full, ...) by just deleting
+//      The same can be done with (..., Index, Sparse, ...) by just deleting
 //      the pointer for the Hyper axis.  The pointer vector contains a
 //      list of constant stride (see below).
 
@@ -523,12 +523,12 @@ language must be Index or Full.
     (pointer present  <------------------>  no pointer   ---\
     no index. --\                           index present   |
     size is     |                           size is      <--/
-    dim [k]  <--/                      -->  nindex[k]
-           \                          /               \
-            \                        /                 \
-             \                      /                   \
-              \                    /                     \
-               \        "Hyper" <--                       --->  "Full"
+    dim [k]  <--/                    /--->  nindex[k]
+           \                        /                 \
+            \                      /                   \
+             \                    /                     \
+              \                  /                       \
+               \        "Hyper" /                         --->  "Full"
                 \-----> (both pointer --\                       no pointer --\
                         and index.      |                       no index     |
                         size is      <--/                       size is  <---/