Fix various rubocop issues.

app/logical/sources/strategies/base.rb

@@ -240,11 +240,6 @@ module Sources
         self.class.to_dtext(artist_commentary_desc)
       end
 
-      # A strategy may return extra data unrelated to the file
-      def data
-        return {}
-      end
-
       # A search query that should return any posts that were previously
       # uploaded from the same source. These may be duplicates, or they may be
       # other posts from the same gallery.

app/logical/sources/strategies/twitter.rb

@@ -139,7 +139,7 @@ module Sources::Strategies
 
     def normalize_tag(tag)
       COMMON_TAG_REGEXES.each do |rg|
-        norm_tag = tag.gsub(rg,"")
+        norm_tag = tag.gsub(rg, "")
         if norm_tag != tag
           return norm_tag
         end