URL parameters from string URLs get doubly URL encoded

[jhominal]

Currently, I have an issue that prevents usage of the last version of httpx:

• I have a URL stored as an str object, that I wish to process;
• That URL contains a query, with a query parameter that is itself an URL containing query parameters. In order to make the specification of that str possible, the query parameters from the URL need to be encoded. However, as slashes are not requiredhave naturally been re-encoded, in which slashes have not been encoded (http://host/path?sub_url=https://other?a%3Db%26c%3Dd);
• httpx double encodes the already existing % characters, sending the http://host/path?sub_url=https:%2F%2Fother?a%253Db%2526c%253Dd - and the server finds itself processing doubly-encoded URL parameters.

I am not really bothered by the fact that slashes get URL-encoded (unlike #2864)

However, I guess my issue is the same as #2863 - I do not think that the % character in my context should be URL encoded.