docs: update Segment analytics to proper package and add simple-analytics (#17513)

* adding simple analytics and changing segment link

* remove empty headline

Author: bcye

docs/docs/adding-analytics.md

@@ -62,8 +62,9 @@ Once this is configured you can deploy your site to test! If you navigate to the
 
 - [Google Tag Manager](/packages/gatsby-plugin-google-tagmanager/)
 - [Google Analytics gtag.js](/packages/gatsby-plugin-gtag/)
-- [Segment](/packages/gatsby-plugin-segment)
+- [Segment](/packages/gatsby-plugin-segment-js)
 - [Amplitude Analytics](/packages/gatsby-plugin-amplitude-analytics)
 - [Fathom](/packages/gatsby-plugin-fathom/)
 - [Baidu](/packages/gatsby-plugin-baidu-analytics/)
 - [Matomo (formerly Piwik)](/packages/gatsby-plugin-matomo/)
+- [Simple Analytics](/packages/gatsby-plugin-simple-analytics)