Suggestions in comments on trigger characters despite setting

_From @Dima4ka on April 21, 2017 1:44_

- VSCode Version: 1.11.2
- OS Version: macOS 10.12.4

Steps to Reproduce:

1. Install C# extension
2. Set:

```
"editor.quickSuggestions": {
"other": true,
"comments": false,
"strings": false
},
```

3. In .cs file write a block comment like this:

```
///
```

4. Put dot in comment (at the end)

### Expected

Nothing shows up

### Actual

Silly suggestion (`!--`) shows up

_Copied from original issue: Microsoft/vscode#25109_