Add missing trailing newlines

lib/gitlab/health_checks/prometheus_text_format.rb

@@ -37,4 +37,4 @@ module Gitlab
       end
     end
   end
-end
\ No newline at end of file
+end

lib/gitlab/metrics.rb

@@ -7,4 +7,4 @@ module Gitlab
       influx_metrics_enabled? || prometheus_metrics_enabled?
     end
   end
-end
\ No newline at end of file
+end

lib/gitlab/metrics/prometheus.rb

@@ -38,4 +38,4 @@ module Gitlab
       end
     end
   end
-end
\ No newline at end of file
+end