message: docs: update documentation to match new empty collection logic
diff: @@ -17,11 +17,12 @@ Container Verification
  If a ``Container`` is marked as required (via the ``required()``) method, then the ``Container`` must
  have a ``Field`` or ``Function`` that was present in the input or contain a sub-``Container`` that does.
  +This does not apply to a ``Container`` that corresponds to an array or dictionary.
  If a ``Container`` corresponds to an array or dictionary, the elements of the array must all be of the requested
  -type. This restriction applies even if the array/dictionary was not marked as ``required``.
  +type, if any were provided. This restriction applies even if the array/dictionary was not marked as ``required``.
  -If a verification lambda was provided via the ``registerVerifier()`` method, this lambda must
  +If a verification function was provided via the ``registerVerifier()`` method, this function must
  return ``true`` when passed the corresponding ``Container`` object.
  .. note::
  @@ -42,7 +43,7 @@ If a range (inclusive upper/lower bounds) of valid values is specified with the
  If a set of valid values is specified with the ``validValues()`` method, both the provided value
  (if applicable) and default value (if specified with ``defaultValue()``) must be included in the set.
  -If a verification lambda was provided via the ``registerVerifier()`` method, this lambda must
  +If a verification function was provided via the ``registerVerifier()`` method, this function must
  return ``true`` when passed the corresponding ``Field`` object.
  Function Verification
  @@ -50,5 +51,5 @@ Function Verification
  If a ``Function`` is marked as required (via the ``required()``) method, then a function must be provided in the input.
  -If a verification lambda was provided via the ``registerVerifier()`` method, this lambda must
  +If a verification function was provided via the ``registerVerifier()`` method, this function must
  return ``true`` when passed the corresponding ``Function`` object.
  