Add mention of heatmap
Add mention of heatmap

lukauskas/seaborn,anntzer/seaborn,anntzer/seaborn,petebachant/seaborn,phobson/seaborn,arokem/seaborn,lukauskas/seaborn,mwaskom/seaborn,arokem/seaborn,mwaskom/seaborn,sauliusl/seaborn,phobson/seaborn