The normal default pretty printer is not great when objects are nested
and it can get hard to read the diff.
Instead, provide a pretty printer that behaves more like when json get
indented, which allows for smaller, more meaningful differences, at
the expense of a slightly longer diff.
This does not touch the other places where the pretty printer is used,
and only updated the full diff one.
New errors:
testing/test_setupplan.py:104:15: E741 ambiguous variable name 'l'
testing/test_setupplan.py:107:15: E741 ambiguous variable name 'l'
extra/get_issues.py:48:29: E741 ambiguous variable name 'l'
testing/test_error_diffs.py:270:32: E741 ambiguous variable name 'l'
Not so sure about it but easier to just fix.
But more importantly, is a large amount of typing-related issues there
were fixed which necessitated noqa's which can now be removed.
The convention is "assert result is expected". Pytest's error diffs now
reflect this. "-" means that sth. expected is missing in the result and
"+" means that there are unexpected extras in the result.
Fixes: #3333
