Merge branch 'fix-markdown-preview-font' into 'master'

Use standard Markdown font in Markdown preview instead of fixed-width font

Closes #2585

See merge request !1414

CHANGELOG

@@ -15,6 +15,7 @@ v 8.0.2 (unreleased)
   - Make commit graphs responsive to window width changes (Stan Hu)
   - Fix top margin for sign-in button on public pages
   - Fix LDAP attribute mapping
+  - Use standard Markdown font in Markdown preview instead of fixed-width font (Stan Hu)
 v 8.0.1
   - Remove git refs used internally by GitLab from network graph (Stan Hu)

app/assets/stylesheets/generic/typography.scss

@@ -110,7 +110,6 @@ textarea.js-gfm-input {
 }
 .md-preview {
-  font-family: $monospace_font;
 }
 .strikethrough {