fix up config page

Author: nicolaskruchten

_posts/plotly_js/fundamentals/config-options/2015-09-24-config-opt-link-text.html

@@ -16,7 +16,7 @@
 
 var config = {
   showLink: true,
-  plotlyServerURL: "https://plotly.com",
+  plotlyServerURL: "https://chart-studio.plotly.com",
   linkText: 'This text is custom!'
 };
 

_posts/plotly_js/fundamentals/config-options/2015-09-24-config-opt-showlink.html

@@ -24,7 +24,7 @@
 
 var config = {
   showLink: true,
-  plotlyServerURL: "https://plotly.com"
+  plotlyServerURL: "https://chart-studio.plotly.com"
 };
 
 Plotly.newPlot('myDiv', data, layout, config);

_posts/plotly_js/fundamentals/config-options/2015-09-24-config-showSendToCloud.html

@@ -18,7 +18,7 @@
 
 var config = {
   showEditInChartStudio: true,
-  plotlyServerURL: "https://plotly.com"
+  plotlyServerURL: "https://chart-studio.plotly.com"
 };
 
 Plotly.newPlot('myDiv', data, layout, config);