Apply suggestions from code review

Author: josevalim

lib/mix/lib/mix/tasks/help.ex

@@ -113,16 +113,18 @@ defmodule Mix.Tasks.Help do
   def run(["app:" <> app]) do
     loadpaths!()
 
-    if Mix.Project.get() do
-      Mix.Task.run("compile")
-    end
-
     app = String.to_atom(app)
 
     # If the application is not available, attempt to load it from Erlang/Elixir
     if is_nil(Application.spec(app, :vsn)) do
-      if Mix.Project.get() do
-        Mix.Task.run("compile")
+      try do
+        Mix.ensure_application!(app)
+      rescue
+        _ ->
+          if Mix.Project.get() do
+            Mix.Task.run("compile")
+          end
+      end
       end
     end