Intermediate fix for indenting huge dicts

[blueyed]

This uses different offsets for the type of pairs: '()' and '[]' will
only look for just 20 lines above, while 1000 lines are used for '{}',
which might be a huge dict.

Ref: #64.

[mgedmin]

FWIW I've had some list literals longer than 20 lines. For example: https://github.com/ManoSeimas/manoseimas.lt/blob/master/manoseimas/scrapy/tests/test_suggestions.py#L770-L806

[blueyed]

@mgedmin
Ok, let's use 100 then for [].

I have some ideas to improve upon this (by doing a quick lookup first and using caching), but this should be good as is for an indermediate fix then.

[mgedmin]

Just had to indent another 80-line list literal. This PR worked fine.