docs(search): set minimum length to 2

With the minimum search length set to 3, it was not possible to search for `$q`.
Changing this to 2 fixes that without really upsetting the search display, since we
only display the first 40 API and 14 non-API items anyway.

Closes #3078
docs(search): fix search submit functionality

When the search input box was submitted (i.e. by pressing enter) the
app was supposed to take you to the first item but this was not happening.
It turns out the app was just reading the wrong property for the path to
the item.

Closes #3078