docs: Fix a few typos

[timgates42]

There are small typos in:

• WHATSNEW.md
• pyfolio/capacity.py
• pyfolio/plotting.py
• pyfolio/round_trips.py
• pyfolio/tears.py
• pyfolio/timeseries.py
• pyfolio/txn.py

Fixes:

• Should read deviations rather than devations.
• Should read deprecation rather than depracation.
• Should read underwater rather than underwaterr.
• Should read transaction rather than transaciton.
• Should read signature rather than signiture.
• Should read positions rather than posistions.
• Should read particular rather than partiulcar.
• Should read parameters rather than pameters.
• Should read originally rather than origionally.
• Should read deviation rather than devation.
• Should read amount rather than ammount.
• Should read overridden rather than overriden.

Semi-automated pull request generated by
https://github.com/timgates42/meticulous/blob/master/docs/NOTE.md