Some scopes used by rescript-vscode have no color

[XiNiHa]

Several scopes that rescript-vscode uses have no color bound in Dracula.

Scopes I found:

• entity.name.namespace
• variable.other/variable.function
• variable.annotation

The full grammar definition is also available: https://github.com/rescript-lang/rescript-vscode/blob/master/grammars/rescript.tmLanguage.json

On Dark+:

On Dracula:

[dsifford]

Feel free to open a PR.