Add csvformat to docs index.
Add csvformat to docs index.

jpalvarezf/csvkit,aequitas/csvkit,bradparks/csvkit__query_join_filter_CSV_cli,gepuro/csvkit,tlevine/csvkit,arowla/csvkit,unpingco/csvkit,nriyer/csvkit,Jobava/csvkit,bmispelon/csvkit,themiurgo/csvkit,haginara/csvkit,kyeoh/csvkit,Tabea-K/csvkit,barentsen/csvkit,snuggles08/csvkit,onyxfish/csvkit,reubano/csvkit,matterker/csvkit,wireservice/csvkit,elcritch/csvkit,doganmeh/csvkit,archaeogeek/csvkit,wjr1985/csvkit,dannguyen/csvkit,KarrieK/csvkit