[html] No values suggested for `autocapitalize`

- VSCode Version: 1.45.0 - OS Version: macOS 10.15.4 Steps to Reproduce: 1. Copy the following to an HTML file: `<div role="" autocapitalize=""></div>` 2. Notice that there is autocompletion for the role's attribute values but, even though VS Code knows about autocapitalize's values (shown when you are autocompleting that attribute), it does not show suggestions for it's values. Does this issue occur when all extensions are disabled? Yes