Update korean-spelling-checker to 1.4.1 and add caveats

Casks/korean-spelling-checker.rb

@@ -1,6 +1,6 @@
 cask :v1 => 'korean-spelling-checker' do
-  version '1.2.1'
-  sha256 'd06e8f563357bc122ab921503e227241646f3b3db932a374236886987ebb07ab'
+  version '1.4.1'
+  sha256 'f38e74be69f86c4c56aa60dfccb189e666979f519f69acbc0f5700442447661f'
 
   # github.com is the official download host per the vendor homepage
   url "https://github.com/miname/Korean-Spelling-Checker-Workflow/archive/#{version}.tar.gz"
@@ -8,5 +8,16 @@ cask :v1 => 'korean-spelling-checker' do
   homepage 'http://appletree.or.kr/google-chrome-extensions/'
   license :mit
 
-  service '✔ 선택한 글의 한국어 맞춤법 검사하기.workflow'
+  service "Korean-Spelling-Checker-Workflow-#{version}/✔ 선택한 글의 한국어 맞춤법 검사하기.workflow"
+
+  uninstall :delete => '~/Library/Services/✔ 선택한 글의 한국어 맞춤법 검사하기.workflow'
+
+  caveats do
+    <<-EOS.undent
+      #{token} only works when you install it manually via Service Installer,
+      so you may need to run the installer with
+
+        open '~/Library/Services/✔ 선택한 글의 한국어 맞춤법 검사하기.workflow'
+    EOS
+  end
 end