Search Enhancement: Change page title with query

### Impacted plugin

Jetpack

### What

Change the of the page with search query to provide better browser history.

### How

### Current behaviour

For now, search URLs in browser history doesn't have meaningful title, like in the following screenshot.


### Changes suggested

Change the <title> of the page with search query to provide better browser history. e.g. "Search result for 'query' - Website name..."

No file or test is named. Start by locating Jetpack's search-page title handling, then check how the query is available when the page is rendered. Done means browser history shows a meaningful title containing the search query and the website name, with coverage for search results.

Written by the indexing model from the issue text.