docs: add Sourcegraph badge

Author: sqs

README.md

@@ -4,6 +4,7 @@
 [![codecov](https://codecov.io/gh/sourcegraph/codeintellify/branch/master/graph/badge.svg?token=1Xk7sdvG0y)](https://codecov.io/gh/sourcegraph/codeintellify)
 [![code style: prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg)](https://github.com/prettier/prettier)
 [![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)
+[![sourcegraph: search](https://img.shields.io/badge/sourcegraph-search-brightgreen.svg)](https://sourcegraph.com/github.com/sourcegraph/codeintellify)
 
 > Adds code intelligence to code views on the web