Adding ref links to Build Charts page

Author: jeff-allen-mongo

source/build-charts.txt

@@ -37,25 +37,25 @@ your data:
 
   - Grouped Column
 
-- Line Charts
+- :ref:`Line Charts <line-area-chart-ref>`
 
   - Discrete Line
 
   - Continuous Line
 
-- Area Charts
+- :ref:`Area Charts <line-area-chart-ref>`
 
   - Stacked Discrete Area
 
   - Continuous Area
 
 - Grid Charts
 
-  - Heatmap
+  - :ref:`Heatmap <heatmap-chart-ref>`
 
-  - Scatter
+  - :ref:`Scatter <scatter-chart-ref>`
 
-- Donut Charts
+- :ref:`Donut Charts <donut-chart-ref>`
 
 Create a Chart
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