graphs: fix stack effect to be more clear on closure.

basis/graphs/graphs-docs.factor

@@ -28,5 +28,5 @@ HELP: remove-vertex
 { $side-effects "graph" } ;
 
 HELP: closure
-{ $values { "obj" object } { "quot" { $quotation "( obj -- assoc )" } } { "assoc" "a new assoc" } }
+{ $values { "vertex" object } { "quot" { $quotation "( vertex -- assoc )" } } { "assoc" "a new assoc" } }
 { $description "Outputs a set of all vertices reachable from " { $snippet "vertex" } " via edges given by the quotation. The set always includes " { $snippet "vertex" } "." } ;

basis/graphs/graphs.factor

@@ -31,7 +31,7 @@ PRIVATE>
 
 <PRIVATE
 
-: (closure) ( obj assoc quot: ( elt -- assoc ) -- )
+: (closure) ( vertex assoc quot: ( vertex -- assoc ) -- )
     2over key? [
         3drop
     ] [
@@ -41,5 +41,5 @@ PRIVATE>
 
 PRIVATE>
 
-: closure ( obj quot -- assoc )
+: closure ( vertex quot: ( vertex -- assoc ) -- assoc )
     H{ } clone [ swap (closure) ] keep ; inline