snapshot/tosvg: clean tspan elements for svg export

Author: antoinerg

src/snapshot/tosvg.js

@@ -88,7 +88,7 @@ module.exports = function toSVG(gd, format, scale) {
     // fill whatever container it's displayed in regardless of plot size.
     svg.node().style.background = '';
 
-    svg.selectAll('text')
+    svg.selectAll('text,tspan')
         .attr({'data-unformatted': null, 'data-math': null})
         .each(function() {
             var txt = d3.select(this);