Update TW assignment names

Why is this change being made?

The Designated TW table isn't displayed properly.
MR !41780 (merged) should have modified tech-writing.html.haml with new TW names.

Review App: https://msj-update-tw-assignment-names.about.gitlab-review.app/handbook/engineering/ux/technical-writing/index.html#assignments

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

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