fix docs

[csernazs]

• test_example_blocking_httpserver.py: remove httpserver.clear()
• doc: add notes about defining responses for the expected requests

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (8110d9d) 95.47% compared to head (3cf02f2) 95.47%. Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #271 +/- ## ======================================= Coverage 95.47% 95.47% ======================================= Files 4 4 Lines 597 597 ======================================= Hits 570 570 Misses 27 27 ```

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[csernazs]

@matez0 fixed the texts according to your suggestion, it made it better, thanks! Please check. If it looks ok for you I would merge it.

[matez0]

@matez0 fixed the texts according to your suggestion, it made it better, thanks! Please check. If it looks ok for you I would merge it.

Looks fine. (If the added exception class reference is correct.)