404 error with message and provide example

src/invidious/routes/search.cr

@@ -55,6 +55,8 @@ module Invidious::Routes::Search
 
       begin
         search_query, count, videos, operators = process_search_query(query, page, user, region: region)
+      rescue ex : ChannelSearchException
+        return error_template(404, "Unable to find channel with id of '#{ex.channel}'. Are you sure that's an actual channel id? It will look like 'UC4QobU6STFB0P71PMvOGN5A'.")
       rescue ex
         return error_template(500, ex)
       end

src/invidious/search.cr

@@ -1,6 +1,7 @@
 class ChannelSearchException < InfoException
-  def initialize(channel : String)
-    super "Unable to find channel with id of '#{channel}'. Are you sure that's an actual channel id?"
+  getter channel : String
+
+  def initialize(@channel)
   end
 end