html: ensure comments are correctly scrubbed

lib/pleroma/html.ex

@@ -43,8 +43,6 @@ defmodule Pleroma.HTML.Scrubber.TwitterText do
   require HtmlSanitizeEx.Scrubber.Meta
   alias HtmlSanitizeEx.Scrubber.Meta
 
-  alias Pleroma.HTML
-
   Meta.remove_cdata_sections_before_scrub()
   Meta.strip_comments()
 
@@ -83,8 +81,6 @@ defmodule Pleroma.HTML.Scrubber.Default do
   require HtmlSanitizeEx.Scrubber.Meta
   alias HtmlSanitizeEx.Scrubber.Meta
 
-  alias Pleroma.HTML
-
   @markup Application.get_env(:pleroma, :markup)
   @uri_schemes Application.get_env(:pleroma, :uri_schemes, [])
   @valid_schemes Keyword.get(@uri_schemes, :valid_schemes, [])
@@ -181,6 +177,8 @@ defmodule Pleroma.HTML.Transform.MediaProxy do
     {"img", attributes, children}
   end
 
+  def scrub({:comment, children}), do: ""
+
   def scrub({tag, attributes, children}), do: {tag, attributes, children}
   def scrub({tag, children}), do: children
   def scrub(text), do: text