(parser-tools.scribl): Typo

not be the -> may not be the

parser-tools-doc/parser-tools/parser-tools.scrbl

@@ -446,8 +446,8 @@ The same as @racket[(complement re ...)].})))
 Each @racket[_action-expr] in a @racket[lexer] form can produce any
 kind of value, but for many purposes, producing a @deftech{token}
 value is useful. Tokens are usually necessary for inter-operating with
-a parser generated by @racket[parser-tools/parser], but tokens not be
+a parser generated by @racket[parser-tools/parser], but tokens may not
-the right choice when using @racket[lexer] in other situations.
+be the right choice when using @racket[lexer] in other situations.
 
 @defform[(define-tokens group-id (token-id ...))]{