### Environment - Editor and Version (VS Code, Atom, Sublime): VS Code 1.29.0 - Your primary theme: Dark+ (default dark) ### Issue Description Double-quoted strings color `@tokens` the same as `$tokens` #### Screenshots  ### Expected Behavior Only `$tokens` or `$(expressions)` are string-interpolated in a double-quoted string. The `@word` is just going to be treated as part of the string. ### Code Samples This may be an appropriate spec test case: ```PowerShell "This is a @double quoted string." # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ string.quoted.double.powershell ```