adding basic helpers to guide users for comments/subscribe to accounts

client/src/app/videos/+video-watch/comment/video-comments.component.html

@@ -1,6 +1,9 @@
 <div>
-  <div class="title-page title-page-single">
-    Comments
+  <div class="title-block">
+    <div class="title-page title-page-single">
+      Comments
+    </div>
+    <my-help *ngIf="video.commentsEnabled === true" helpType="custom" customHtml="You can either comment on the page of your instance where this video is federated with your PeerTube account, or via any ActivityPub-capable fediverse instance. For instance with Mastodon or Pleroma you can type in the search box <strong>@{{video.account.displayName}}@{{video.account.host}}</strong> and find back the video. Direct commenting capabilities are being worked on in <a href='https://github.com/Chocobozzz/PeerTube/issues/224'>#224</a>."></my-help>
   </div>
 
   <ng-template [ngIf]="video.commentsEnabled === true">

client/src/app/videos/+video-watch/comment/video-comments.component.scss

@@ -19,6 +19,14 @@
   font-size: 13px;
 }
 
+.title-block .title-page {
+  margin-right: 0;
+}
+
+my-help {
+  display: inline-block;
+}
+
 @media screen and (max-width: 600px) {
   .view-replies {
     margin-left: 46px;

client/src/app/videos/+video-watch/video-watch.component.html

@@ -21,6 +21,7 @@
               {{ video.channel.displayName }}
             </a>
             <!-- Here will be the subscribe button -->
+            <my-help helpType="custom" customHtml="You can subscribe to this account via any ActivityPub-capable fediverse instance. For instance with Mastodon or Pleroma you can type in the search box <strong>@{{video.account.displayName}}@{{video.account.host}}</strong> and subscribe there. Subscription as a PeerTube user is being worked on in <a href='https://github.com/Chocobozzz/PeerTube/issues/470'>#470</a>."></my-help>
           </div>
 
           <div class="video-info-by">

client/src/app/videos/+video-watch/video-watch.component.scss

@@ -76,6 +76,10 @@
             opacity: 0.8;
           }
         }
+
+        my-help {
+          display: inline-block;
+        }
       }
 
       .video-info-by a {