Remove Slack from site and repo docs (#36825)

* Remove Slack from site and repo docs

* Apply suggestions from code review

Co-authored-by: Julien Déramond <julien.deramond@orange.com>

Co-authored-by: Julien Déramond <julien.deramond@orange.com>

README.md

@@ -58,7 +58,6 @@ Read the [Getting started page](https://getbootstrap.com/docs/5.2/getting-starte
 
 ## Status
 
-[![Slack](https://bootstrap-slack.herokuapp.com/badge.svg)](https://bootstrap-slack.herokuapp.com/)
 [![Build Status](https://img.shields.io/github/workflow/status/twbs/bootstrap/JS%20Tests/main?label=JS%20Tests&logo=github)](https://github.com/twbs/bootstrap/actions?query=workflow%3AJS+Tests+branch%3Amain)
 [![npm version](https://img.shields.io/npm/v/bootstrap)](https://www.npmjs.com/package/bootstrap)
 [![Gem version](https://img.shields.io/gem/v/bootstrap)](https://rubygems.org/gems/bootstrap)
@@ -178,7 +177,7 @@ Get updates on Bootstrap's development and chat with the project maintainers and
 
 - Follow [@getbootstrap on Twitter](https://twitter.com/getbootstrap).
 - Read and subscribe to [The Official Bootstrap Blog](https://blog.getbootstrap.com/).
-- Join [the official Slack room](https://bootstrap-slack.herokuapp.com/).
+- Ask and explore [our GitHub Discussions](https://github.com/twbs/bootstrap/discussions).
 - Chat with fellow Bootstrappers in IRC. On the `irc.libera.chat` server, in the `#bootstrap` channel.
 - Implementation help may be found at Stack Overflow (tagged [`bootstrap-5`](https://stackoverflow.com/questions/tagged/bootstrap-5)).
 - Developers should use the keyword `bootstrap` on packages which modify or add to the functionality of Bootstrap when distributing through [npm](https://www.npmjs.com/browse/keyword/bootstrap) or similar delivery mechanisms for maximum discoverability.