Update ROADMAP (#20002)

* Tidy up formatting
* IRC Meetings are the best place to get feedback (due to having an agenda and a large number of Core Team members active)
* Don't repeat the 2.4 ETA, it should only exist in `ROADMAP_2_4.rst`

ROADMAP.rst

@@ -9,14 +9,15 @@ The roadmap will be updated by version. Based on team and community feedback, an
 
 These roadmaps are the team's *best guess* roadmaps based on the Ansible team's experience and are also based on requests and feedback from the community.  There are things that may not make it on due to time constraints, lack of community maintainers, etc.  And there may be things that got missed, so each roadmap is published both as an idea of what is upcoming in Ansible, and as a medium for seeking further feedback from the community. Here are the good places for you to submit feedback:
 
-  - Ansible's google-group: ansible-devel
+- Add to the agenda of a `Core IRC Meetings <https://github.com/ansible/community/blob/master/MEETINGS.md>`_ (preferred)
-  -  Ansible Fest conferences.
+- Ansible's google-group: ansible-devel
-  - IRC freenode channel: #ansible-devel (this one may have things lost in lots of conversation, so a caution).
+- AnsibleFest conferences.
+- IRC freenode channel: #ansible-devel (this one may have things lost in lots of conversation, so a caution).
 
 =======================================
 Current 2.4 Roadmap is open for comment
 =======================================
-We are starting to build the 2.4 Roadmap, targeted for June/July delivery.  We are seeking community feedback!  That document is here:
+We are starting to build the 2.4 Roadmap. We are seeking community feedback! That document is here:
  - `2.4 Roadmap Document <docs/docsite/rst/roadmap/ROADMAP_2_4.rst>`_