Fix colormap article link (closes #693)
Fix colormap article link (closes #693)

anntzer/seaborn,sauliusl/seaborn,lukauskas/seaborn,olgabot/seaborn,lukauskas/seaborn,arokem/seaborn,phobson/seaborn,mwaskom/seaborn,petebachant/seaborn,phobson/seaborn,arokem/seaborn,JWarmenhoven/seaborn,mwaskom/seaborn,anntzer/seaborn,oesteban/seaborn,drewokane/seaborn