Reduce the file size of the landing page (#1105)

* Update suggestions.md

* Add announcement of the paper book release

* Fix size of svg

* Update contrib rocks image

* Optimize HTML of the landing page

* Fix the line breaks

mkdocs.yml

@@ -20,7 +20,7 @@ theme:
   custom_dir: build/overrides
   language: zh
   features:
-    # - announce.dismiss
+    - announce.dismiss
     - content.action.edit
     # - content.action.view
     - content.code.annotate