Code comments improvements (#15722)

- Right-align the Reply and Resolve buttons
- Center Resolved text and add some padding
- Add padding to inline comments
- Indent the comment content to align with author name
- Re-parent form to allow better button layout space.

Co-authored-by: zeripath <art27@cantab.net>

templates/repo/diff/comment_form.tmpl

@@ -1,9 +1,4 @@
 {{if and $.root.SignedUserID (not $.Repository.IsArchived)}}
-	{{if $.hidden}}
-		<button class="comment-form-reply ui green labeled icon tiny button">
-			{{svg "octicon-reply" 16 "reply icon mr-2"}}{{$.root.i18n.Tr "repo.diff.comment.reply"}}
-		</button>
-	{{end}}
 	<form class="ui form {{if $.hidden}}hide comment-form comment-form-reply{{end}}" action="{{$.root.Issue.HTMLURL}}/files/reviews/comments" method="post">
 	{{$.root.CsrfTokenHtml}}
 		<input type="hidden" name="origin" value="{{if $.root.PageIsPullFiles}}diff{{else}}timeline{{end}}">
@@ -26,7 +21,7 @@
 			{{.i18n.Tr "loading"}}
 			</div>
 		</div>
-		<div class="field footer">
+		<div class="field footer mx-3">
 			<span class="markup-info">{{svg "octicon-markup"}} {{$.root.i18n.Tr "repo.diff.comment.markup_info"}}</span>
 			<div class="ui right">
 				{{if $.reply}}