Update Url class to common syntax about datatypes HOT 4 OPEN

I guess the query string is also called the query string:

A URL’s query is either null or an ASCII string. It is initially null.

So I guess it is called URLSearchParams when parsed, and query when a string attached to the full url

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Also, I want to make sure query strings are parsed and built correctly, so:

foo[bar][0][che]=happy

would convert to:

foo = {
  bar: [
    {
      che: happy
    }
  ]
}

and likewise, if you passed that dict into the url builder it would convert back to foo[bar][0][che]=happy

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I think query_params for the parsed query of the Url is pretty good. That's what I changed dsnparse's parsed query string to. RFC3986 section 3.4 doesn't give a good name for the actual assignment statements of each part of the query

from datatypes.

Postgres calls the query part paramspec

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