Update ext-dep-index.md
Update ext-dep-index.md

Formatting.
UniversalDependencies/docs,coltekin/docs,fginter/docs-fginterfork,coltekin/docs,fginter/docs,PhyloStar/UDTelugu,fginter/docs,fginter/docs,UniversalDependencies/docs,coltekin/docs,coltekin/docs,PhyloStar/UDTelugu,fginter/docs-fginterfork,fginter/docs,UniversalDependencies/docs,UniversalDependencies/docs,PhyloStar/UDTelugu,coltekin/docs,fginter/docs,fginter/docs-fginterfork,PhyloStar/UDTelugu,UniversalDependencies/docs,fginter/docs-fginterfork,PhyloStar/UDTelugu,fginter/docs-fginterfork,PhyloStar/UDTelugu,UniversalDependencies/docs