remove support for deprecated 'annotation.ref' attribute (use 'annotation.xref' and 'annotation.yref' instead)

Author: emilykl

src/components/annotations/attributes.js

@@ -487,14 +487,4 @@ module.exports = templatedArray('annotation', {
         ].join(' ')
     },
     editType: 'calc',
-
-    _deprecated: {
-        ref: {
-            valType: 'string',
-            editType: 'calc',
-            description: [
-                'Obsolete. Set `xref` and `yref` separately instead.'
-            ].join(' ')
-        }
-    }
 });

src/plot_api/helpers.js

@@ -144,17 +144,6 @@ exports.cleanLayout = function(layout) {
 
         if(!Lib.isPlainObject(ann)) continue;
 
-        if(ann.ref) {
-            if(ann.ref === 'paper') {
-                ann.xref = 'paper';
-                ann.yref = 'paper';
-            } else if(ann.ref === 'data') {
-                ann.xref = 'x';
-                ann.yref = 'y';
-            }
-            delete ann.ref;
-        }
-
         cleanAxRef(ann, 'xref');
         cleanAxRef(ann, 'yref');
     }