update accel abm formatting

Matthewrequested to merge
patch-19826112268859201 into master

Why is this change being made?

This is simply an update to handbook formatting, created to make it simpler and more efficient to navigate.

  • fixing broken table in "Issue Board & Labels" section
  • removing subheaders from "Strategy & Tactics" section for simpler navigation

Author Checklist

  • Provided a concise title for the MR
  • Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
  • Assign this change to the correct DRI
    • If the DRI for the page/s being updated isn’t immediately clear, then assign it to your manager.
    • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
    • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files.

For help with failing pipelines reach out in #mr-buddies in Slack

Merge request reports