[5.x] Don't enforce a query length on comb searches

[ryanmitchell]

Sometimes you want to show users a list of results, and then allow a query to be entered that filters that listing, rather than entering the query before showing the listing.

As things stand that means using the collection tag for the non-query state, and then the search:results tag for the queried state. This is because the Comb search driver doesn't allow blank queries. This isn't ideal and means a lot of code repetition for what is the same thing.

This PR updates the logic to allow blank queries when you have 'min_characters' => 0 in your search index config. This allows you to use the search:results tag for both situations mentioned above:

{{ search:results for="{get:q ?? '*'}" as="results" }}

This shouldn't break any existing installs as min_characters: 1 is the default (?).

I left the NoQuery class in place on the off chance someone might be using it.

[jasonvarga]

I think you should maybe leave it as it was, but change the NoQuery condition to if ($length === 0 && $this->min_characters > 0) {

Then things will work exactly the same for everyone, but if you set your min_characters config to 0, you can go ahead and search for nothing.

[ryanmitchell]

Good idea