Update index.md
Update index.md

- remove tabs in example source code for more consistent look
- example source code psr reformatted
floriansemm/SolrBundle,frank-und-freunde/SolrBundle,drdk/SolrBundle,zquintana/SunSearchBundle,cegeka/fd-solr-bundle,andythorne/SolrBundle,floriansemm/SolrBundle,zquintana/SunSearchBundle,drdk/SolrBundle,clarity-project/SolrBundle,clarity-project/SolrBundle,starsystemsindia/SolrBundle