docs: fix D3 capitalisation; d3 -> D3 (#27)
docs: fix D3 capitalisation; d3 -> D3 (#27)

jleft/d3-financial-components,jleft/d3-financial-components,ScottLogic/d3fc,d3fc/d3fc,ScottLogic/d3fc,ColinEberhardt/d3fc,chrisprice/d3fc,chrisprice/d3fc,d3fc/d3fc,ColinEberhardt/d3fc,ColinEberhardt/d3fc,jleft/d3-financial-components,d3fc/d3fc,ScottLogic/d3fc,chrisprice/d3fc,d3fc/d3fc