Issue Type: Bug

I'm using JavaScript but this is likely not language-specific:

1. Start typing a comment
   // something like, if ( true )
2. Type an opening brace
   // something like, if ( true ) {
3. Editor will insert a closing brace, cursor will be between braces
   // something like, if ( true ) {|}
4. Hit Enter / Return

Expected:
Newline will automatically be in a commented-out line

    // something like, if ( true ) {
    // }

Actual:
The comment is treated like code and an extra newline is inserted, introducing a hanging end-brace:

   // something like, if ( true ) {
       
   }      

VS Code version: Code 1.38.0 (3db7e09, 2019-09-03T21:47:00.464Z)
OS version: Darwin x64 17.7.0