don't fetch completions on opening template tag

[jasonwilliams]

I found that VSCode was trying to fetch completions from typescript-styled-plugin on the opening of 2 backticks ``.
This casues some issues:

1. Other snippets (like the expanding of the backticks) ends up getting lost in the results, and VSCode will focus on the css style you used last.
2. Due to the amount of completions the CSS language server returns, the time taken for it to respond can be slow.
3. The UX is not right, It's unlikely the user wants completions at this stage, they are either going to hit enter, or start typing something.

Before:

After:

Fixes: styled-components/vscode-styled-components#276

@mjbvz

[mjbvz]

Yes I agree this makes sense. Merging and will publish new build shortly