Corrected command to unregister Gitea (#74)

* Update windows-service.en-us.md

Corrected command to unregister Gitea

* Update windows-service.zh-cn.md

Corrected command to unregister Gitea

* Update windows-service.zh-tw.md

Corrected command to unregister Gitea

Author: dalito

content/doc/installation/windows-service.en-us.md

@@ -30,5 +30,5 @@ After, open "Windows Services", search for the service named "gitea", right-clic
 To unregister Gitea as a service, open `cmd` as an Administrator and run:
 
 ```
-sc remove gitea
+sc delete gitea
 ```

content/doc/installation/windows-service.zh-cn.md

@@ -30,5 +30,5 @@ sc create gitea start= auto binPath= ""C:\gitea\gitea.exe" web --config "C:\gite
 以Administrator身份运行 `cmd`，然后执行以下命令：
 
 ```
-sc remove gitea
+sc delete gitea
 ```

content/doc/installation/windows-service.zh-tw.md

@@ -30,5 +30,5 @@ sc create gitea start= auto binPath= ""C:\gitea\gitea.exe" web --config "C:\gite
 要刪除 Gitea 服務，請用管理者身份執行 `cmd` 並且執行底下指令：
 
 ```
-sc remove gitea
+sc delete gitea
 ```