Duplicated file extension in save dialog

[aeschli]

From #105463 (comment)

Java extension added the following section to package.json.

{
  "contributes":
   {
    "languages": [
      {
        "id": "java",
        "extensions": [
          ".java"
          ".class"
        ],
        "configuration": "./language-configuration.json"
      }
    ]
  }