Fix typo in documentation example
    
        | author | Steve Losh <steve@stevelosh.com> | 
    
        | date | Mon, 05 Apr 2021 21:57:55 -0400 | 
    
    
        | parents | 64235de41c38 | 
    
        | children | 4518e61a96c6 | 
    
        | branches/tags | (none) | 
    
        | files | docs/02-usage.markdown | 
Changes
    
--- a/docs/02-usage.markdown	Sun Mar 14 21:32:22 2021 -0400
+++ b/docs/02-usage.markdown	Mon Apr 05 21:57:55 2021 -0400
@@ -409,7 +409,7 @@
     (digraph:insert-edge *d* 'c 'a) ; c depends on a
 
     (handler-case (digraph:topological-sort *d*)
-      (digraph:topological-sort-cycle-error (c)
+      (digraph:topological-sort-cycle (c)
         (list :cyclic (digraph:vertex-involved c))))
     ; =>
     ; (:CYCLIC A)