Pragma removes '//' from value when uncommenting

[chodyo]

🐛 Describe the bug
If an uncommented pragma value contains the text //, the // is removed from the value.

For example, if a URL with protocol has a value of http://example.com, it will be uploaded to the remote gist with a value of http:example.com.

🌴 Visual Studio Code Version : [ 1.33.1 ]
🌴 Code Settings Sync Version : [ 3.2.9 ]
🌴 Standard or Insiders : [ Standard ]
🌴 Portable or Installed : [ Installed ]
🌴 OSS or Official Build : [ Official ]
🌴 Operating System : [ Windows 10 ]
🌴 Occurs On: [ Upload ]
🌴 Proxy Enabled: [ Yes ]
🌴 Gist Id: [ n/a ]

📰 To Reproduce
Steps to reproduce the behavior:

1. Create a pragma that in use by the current machine pragma settings. It should be uncommented and contain // somewhere in the json's value.
2. Upload settings
3. Check uploaded value (view on web or force download). // is now missing from the key.

💪 Expected behavior
Keys should never be modified on upload or download.

📺 Console Error Log
n/a

📺 Additional context

// local settings
{
    // @sync host=home-desktop-pc
//    "http.proxy": "",
    // @sync host=work-laptop
    "http.proxy": "http://127.0.0.1:8888"
}
// remote upload
{
    // @sync host=home-desktop-pc
    "http.proxy": "",
    // @sync host=work-laptop
    "http.proxy": "http:127.0.0.1:8888"
}

[shanalikhan]

Duplicate of #865