More tweaks to make note edit/preview CSS consistent

Closes #2585

app/assets/stylesheets/generic/typography.scss

@@ -105,6 +105,10 @@ textarea.js-gfm-input {
   font-family: $monospace_font;
 }
+.md-preview {
+  font-family: $monospace_font;
+}
+
 .strikethrough {
   text-decoration: line-through;
 }

app/assets/stylesheets/pages/note_form.scss

@@ -109,7 +109,7 @@
 .note-edit-form {
   display: none;
-  font-size: 13px;
+  font-size: 15px;
   .form-actions {
     padding-left: 20px;

app/views/projects/notes/_edit_form.html.haml

 .note-edit-form
   = form_for note, url: namespace_project_note_path(@project.namespace, @project, note), method: :put, remote: true, authenticity_token: true do |f|
     = note_target_fields(note)
-    = render layout: 'projects/md_preview', locals: { preview_class: 'note-text' } do
+    = render layout: 'projects/md_preview', locals: { preview_class: 'md-preview' } do
       = render 'projects/zen', f: f, attr: :note, classes: 'note_text js-note-text js-task-list-field'
       = render 'projects/notes/hints'

app/views/projects/notes/_form.html.haml

@@ -7,7 +7,7 @@
   = f.hidden_field :noteable_id
   = f.hidden_field :noteable_type
-  = render layout: 'projects/md_preview', locals: { preview_class: "note-text", referenced_users: true } do
+  = render layout: 'projects/md_preview', locals: { preview_class: "md-preview", referenced_users: true } do
     = render 'projects/zen', f: f, attr: :note, classes: 'note_text js-note-text'
     = render 'projects/notes/hints'
     .error-alert