Fix deprecation warning for go.Annotations. (plotly#1138)

There is no go.layout.Annotations (it should not have been plural)

Author: jonmmease

codegen/compatibility.py

@@ -11,7 +11,7 @@
          'new': ['Scatter', 'Bar', 'Area', 'Histogram', 'etc.']},
     'Annotations':
         {'base_type': list,
-         'new': ['layout', 'layout.scene']},
+         'new': ['layout.Annotation', 'layout.scene.Annotation']},
     'Frames':
         {'base_type': list,
          'new': ['Frame']},

plotly/graph_objs/_deprecations.py

@@ -45,24 +45,24 @@ class Annotations(list):
     """
     plotly.graph_objs.Annotations is deprecated.
 Please replace it with a list or tuple of instances of the following types
-  - plotly.graph_objs.layout.Annotations
-  - plotly.graph_objs.layout.scene.Annotations
+  - plotly.graph_objs.layout.Annotation
+  - plotly.graph_objs.layout.scene.Annotation
 
     """
 
     def __init__(self, *args, **kwargs):
         """
         plotly.graph_objs.Annotations is deprecated.
 Please replace it with a list or tuple of instances of the following types
-  - plotly.graph_objs.layout.Annotations
-  - plotly.graph_objs.layout.scene.Annotations
+  - plotly.graph_objs.layout.Annotation
+  - plotly.graph_objs.layout.scene.Annotation
 
         """
         warnings.warn(
             """plotly.graph_objs.Annotations is deprecated.
 Please replace it with a list or tuple of instances of the following types
-  - plotly.graph_objs.layout.Annotations
-  - plotly.graph_objs.layout.scene.Annotations
+  - plotly.graph_objs.layout.Annotation
+  - plotly.graph_objs.layout.scene.Annotation
 """, DeprecationWarning
         )
         super(Annotations, self).__init__(*args, **kwargs)