fix: documentation of Marshal
the "strict" keyword mentioned in the documentation does not exist
anymore
@@ -69,8 +69,7 @@ type Subgrapher interface {
// Marshal returns the DOT encoding for the graph g, applying the prefix
// and indent to the encoding. Name is used to specify the graph name. If
// name is empty and g implements Graph, the returned string from DOTID
-// will be used. If strict is true the output bytes will be prefixed with
-// the DOT "strict" keyword.
+// will be used.
//
// Graph serialization will work for a graph.Graph without modification,
// however, advanced GraphViz DOT features provided by Marshal depend on
