Svelte: Maintain search query in search input

[taiyab]

In the Svelte prototype, we override the search query to be scoped to the repo you're in by default, essentially eliminating the query you entered prior.

This essentially clears any careful query a user may have crafted to get to this destination, which is undesirable without a way of at least getting it back easily.

We should update this by either:

• Presenting the last search query you made, already prepopulated in the input
• OR, continue to overwrite the query with this new one (for easy repo scoped searches), but allow you to quickly select and rerun your last search query