legend: add logic for 'ohlc' and 'candlestick' in legend name edits

- so that editing legend item text restyles increasing / decreasing
  'name' instead of trace-wide name

Author: etpinard

src/components/legend/draw.js

@@ -367,10 +367,27 @@ function drawTexts(g, gd) {
             .call(textLayout)
             .on('edit', function(text) {
                 this.attr({'data-unformatted': text});
+
                 this.text(text)
                     .call(textLayout);
+
                 if(!this.text()) text = ' \u0020\u0020 ';
-                Plotly.restyle(gd, 'name', text, traceIndex);
+
+                var fullInput = legendItem.trace._fullInput || {},
+                    astr;
+
+                // N.B. this block isn't super clean,
+                // and only works for for 'ohlc' and 'candlestick',
+                // but should be generalized for other one-to-many transforms
+                if(['ohlc', 'candlestick'].indexOf(fullInput.type) !== -1) {
+                    var transforms = legendItem.trace.transforms,
+                        direction = transforms[transforms.length - 1].direction;
+
+                    astr = direction + '.legenditem.name';
+                }
+                else astr = 'name';
+
+                Plotly.restyle(gd, astr, text, traceIndex);
             });
     }
     else text.call(textLayout);