C# syntax highlighting is broken by multiline types

Originally from @svenskmand in https://github.com/microsoft/vscode/issues/96341

- VSCode Version:
Version: 1.44.2 (system setup)
Commit: ff915844119ce9485abfe8aa9076ec76b5300ddd
Date: 2020-04-16T16:36:23.138Z
Electron: 7.1.11
Chrome: 78.0.3904.130
Node.js: 12.8.1
V8: 7.8.279.23-electron.0
OS: Windows_NT x64 10.0.18363
- OS Version: Windows 10

Steps to Reproduce:

1. Open a new C# file and input the following code
```
namespace Foo {
public interface IBar {
IList Baz(IList>>>>>>> foobar);
}
}
```
2. The type of the `foobar` variable and the rest of the method has a white text color and no syntax highlighting.

This is how the syntax highlighting looks before the line break:

This is how the syntax highlighting looks with the line break:

Does this issue occur when all extensions are disabled?: Yes