Improve output message of "MoreFluent" style

[dakusui]

In case, we use "WHEN" phrase but no transformation is given, we see the following output.

"Doe"               ->WHEN:treatAs[NOUT]    ->"Doe"
                      THEN:&&              ->true
                          isNotNull        ->true
                          !                ->true
                            isEmpty        ->false
["John","Doe","PhD"]->WHEN:treatAsList     ->["John","Doe","PhD"]
                      THEN:contains["Doe_"]->true

The part treatAs[NOUT] is an internal term and if it is treatAsIs, the output will be more readable.