Fix discussion reply holder padding

app/assets/stylesheets/framework/timeline.scss

@@ -36,6 +36,7 @@
   &:target,
   &.target {
     background: $line-target-blue;
+    margin-bottom: $gl-padding;
 
     &.system-note .note-body .note-text.system-note-commit-list::after {
       background: linear-gradient(rgba($line-target-blue, 0.1) -100px, $line-target-blue 100%);

app/assets/stylesheets/pages/note_form.scss

@@ -178,7 +178,7 @@
 
 table {
   .discussion-form-container {
-    padding: $gl-padding-top $gl-padding $gl-padding;
+    padding: $gl-padding;
   }
 }
 
@@ -236,22 +236,17 @@ table {
   }
 }
 
-.discussion-body {
+.discussion-body,
+.commit-diff {
   .discussion-reply-holder {
     background-color: $white-light;
     border-radius: 0 0 3px 3px;
-    padding: 0 $gl-padding 10px;
+    padding: $gl-padding;
 
     &.is-replying {
       padding-bottom: $gl-padding;
     }
   }
-
-  .diff-file {
-    .discussion-reply-holder {
-      padding: 10px 16px;
-    }
-  }
 }
 
 .discussion-with-resolve-btn {

app/assets/stylesheets/pages/notes.scss

@@ -14,7 +14,7 @@ $note-form-margin-left: 72px;
 }
 
 @mixin outline-comment() {
-  margin: $gl-padding;
+  margin: $gl-padding $gl-padding 0;
   border: 1px solid $border-color;
   border-radius: $border-radius-default;
 }
@@ -526,10 +526,6 @@ $note-form-margin-left: 72px;
   .notes_content {
     background-color: $white-light;
   }
-
-  .discussion-reply-holder {
-    border-top: 1px solid $border-color;
-  }
 }
 
 .discussion-header,