Fix titles case and add missing punctuation marks (#28713)

* Fix titles case and add missing punctuation marks

* Revert title case

README.md

@@ -36,8 +36,8 @@ If you're interested in contributing to the Grafana project:
 
 ## Get involved
 
-- Follow [@grafana on Twitter](https://twitter.com/grafana/)
-- Read and subscribe to the [Grafana blog](https://grafana.com/blog/)
+- Follow [@grafana on Twitter](https://twitter.com/grafana/).
+- Read and subscribe to the [Grafana blog](https://grafana.com/blog/).
 - If you have a specific question, check out our [discussion forums](https://community.grafana.com/).
 - For general discussions, join us on the [official Slack](http://slack.raintank.io/) team.