refactor(backend): change naming of function names to avoid the is_ prefix

Following Credo.Check.Readability.PredicateFunctionNames check

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/federation/activity_stream/converter/comment.ex

@@ -62,7 +62,7 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Comment do
           tags: fetch_tags(tag_object),
           mentions: fetch_mentions(tag_object),
           local: is_nil(actor_domain),
-          visibility: if(Visibility.is_public?(object), do: :public, else: :private),
+          visibility: if(Visibility.public?(object), do: :public, else: :private),
           published_at: object["published"],
           is_announcement: Map.get(object, "isAnnouncement", false)
         }

lib/federation/activity_stream/converter/event.ex

@@ -77,7 +77,7 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Event do
           category: Categories.get_category(object["category"]),
           visibility: visibility,
           join_options: Map.get(object, "joinMode", "free"),
-          local: is_local?(object["id"]),
+          local: local?(object["id"]),
           external_participation_url: object["externalParticipationUrl"],
           options: options,
           metadata: metadata,
@@ -305,8 +305,8 @@ defmodule Mobilizon.Federation.ActivityStream.Converter.Event do
     )
   end
 
-  @spec is_local?(String.t()) :: boolean()
-  defp is_local?(url) do
+  @spec local?(String.t()) :: boolean()
+  defp local?(url) do
     %URI{host: url_domain} = URI.parse(url)
     %URI{host: local_domain} = URI.parse(Endpoint.url())
     url_domain == local_domain