This commit indents the contents of a `code-block` in `httpclient.nim`
so that it displays correctly. The bug was introduced by 42a64245f8.
I did a quick search for other `code-block`s that are broken in the same
way, but the only other one I found (in `pegs.nim`) is not included in
the generated documentation.
(cherry picked from commit 1e484ed62b)