docs: Fix a few typos

[timgates42]

There are small typos in:

• ember/app/sentry.js
• skylines/api/views/flights.py
• skylines/model/flight.py

Fixes:

• Should read synchronously rather than syncronously.
• Should read cancellation rather than cancelation.
• Should read chunk rather than chunck.

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