Replace link with button in index notifications

app/views/notifications/index.html.erb

@@ -5,10 +5,10 @@
       <%= t("notifications.index.title") %>
     </h1>
 
-    <%= link_to t("notifications.index.mark_all_as_read"),
-                mark_all_as_read_notifications_path,
-                method: :put,
-                class: "button hollow float-right-medium" %>
+    <%= button_to t("notifications.index.mark_all_as_read"),
+                  mark_all_as_read_notifications_path,
+                  method: :put,
+                  class: "button hollow float-right-medium" %>
 
     <ul class="menu simple clear">
       <li class="is-active">

spec/system/notifications_spec.rb

@@ -74,7 +74,7 @@ describe "Notifications" do
     click_notifications_icon
 
     expect(page).to have_css(".notification", count: 2)
-    click_link "Mark all as read"
+    click_button "Mark all as read"
 
     expect(page).to have_css(".notification", count: 0)
   end