Conciseness and fixed some typos in apt.html.md
Conciseness and fixed some typos in apt.html.md

As discussed with Laura, submitting this PR.
ewbankkit/terraform,rnaveiras/terraform,tommynsong/terraform,ewbankkit/terraform,ewbankkit/terraform,hashicorp/terraform,ewbankkit/terraform,tommynsong/terraform,rnaveiras/terraform,tommynsong/terraform,hashicorp/terraform,rnaveiras/terraform,hashicorp/terraform