fixed h3, h4 font-sizing for gitlab-flavored markdown (solves issue #6211)
Created by: brittlewis12
GitLab Markdown Documentation shows h2 & h3 as being different font-sizes, correctly; however, currently only the padding is different in the sass mixin. This issue was opened by @rskuipers in issue #6211.
The README displays the proper font sizes, which should be: h3 {font-size: 1.5em} h4 {font-size: 1.2em}