Pagination unescapes unrelated parameters

[dmolesUC]

Following on to #112 -- it seems like the same code:

links[page_name] = original_url + CGI.unescape(
  original_params.to_query
)

is having the (maybe?) unintended consequence of unescaping previously escaped parameters. Say I have a Rails route returning JSON:API, with a request URL like so:

http://example.test/resources?filter[genre_form]=Advertising+cards

When I include JSONAPI::Pagination in my controller, I get this links block:

    "links": {
        "self":    "http://example.test/resources?filter[genre_form]=Advertising+cards",
        "current": "http://example.test/resources?filter[genre_form]=Advertising cards&page[number]=1"
    }

The page number has been appended, which is good; the +-encoded space in filter[genre_form]=Advertising+cards has been decoded, which seems sketchy.

As with #112, maybe I'm just missing something about the design intent here, but I'd expect the original query to stay intact, and just have the page params set.