Unexpected suggestion in debug console for variable named _

[stevencl]

• VSCode Version: 1.5.0-insiders
• OS Version: Windows 10

Steps to Reproduce:

1. Create a node app, require lodash and assign to a variable named _ (e.g., var _ = require('lodash');
2. Set a breakpoint in code, type _ in the debug.console
3. Expect to see suggestions for lodash, instead see suggestions that contain an underscore:

[stevencl]

Found while testing #10997