Include query string in req_dry_run() output

[wikisqueaks]

curl::curl_echo() splits the request into separate path and query
fields, but only path was used, so the printed request line and the
returned list both omitted the query. The httr2 1.0.0 blog post shows
HEAD /?param=value HTTP/1.1, so this appears to be a regression.

query is returned verbatim, including the leading ? that httpuv puts
in QUERY_STRING — happy to strip it if you'd rather it matched path.

Existing snapshots are unchanged, since they all use query-less URLs.

Fixes #868.

[wikisqueaks]

The failing check is a pull_request_target workflow that can't check out fork code under the new actions/checkout default. It won't affect PRs from branches in the repo, only forks. R-CMD-check passes.