Fix validators documentation (#926)

* Fix validators documentation

* Update validators.py

* Update json_factory.py

Author: tcm0116

openhtf/output/callbacks/json_factory.py

@@ -27,7 +27,7 @@ class OutputToJSON(callbacks.OutputToFile):
     '/data/test_records/%(dut_id)s.%(start_time_millis)s'
   To use this output mechanism:
     test = openhtf.Test(PhaseOne, PhaseTwo)
-    test.add_output_callback(openhtf.output.callbacks.OutputToJson(
+    test.add_output_callback(openhtf.output.callbacks.OutputToJSON(
         '/data/test_records/{dut_id}.{metadata[test_name]}.json'))
 
   Args:

openhtf/util/validators.py

@@ -5,9 +5,8 @@
 module, and will typically be a type, instances of which are callable:
 
   from openhtf.util import validators
-  from openhtf.util import measurements
 
-  class MyLessThanValidator(ValidatorBase):
+  class MyLessThanValidator(validators.ValidatorBase):
     def __init__(self, limit):
       self.limit = limit
 
@@ -35,7 +34,7 @@ def LessThan4(value):
     return value < 4
 
   @measurements.measures(
-      measurements.Measurement('my_measurement).with_validator(LessThan4))
+      measurements.Measurement('my_measurement').with_validator(LessThan4))
   def MyPhase(test):
     test.measurements.my_measurement = 5  # Will also 'FAIL'