Add the total number of features in a release to the intro of the release post

Why is this change being made?

This came up while working on the Keynote for GitLab Commit with Sid. This MR proposes that we include the total # of new features in a release in the final introductory paragraph of the release post.

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what