doc(oneof): mention 'enum'

Author: Crocmagnon

doc.go

@@ -489,7 +489,7 @@ For strings, ints, and uints, oneof will ensure that the value
 is one of the values in the parameter.  The parameter should be
 a list of values separated by whitespace. Values may be
 strings or numbers. To match strings with spaces in them, include
-the target string between single quotes.
+the target string between single quotes. Kind of like an 'enum'.
 
 	Usage: oneof=red green
 	       oneof='red green' 'blue yellow'