docs: Fix a few typos

[timgates42]

There are small typos in:

• pyte/control.py
• pyte/screens.py
• tests/test_diff.py
• tests/test_screen.py

Fixes:

• Should read erasable rather than eraseable.
• Should read beginning rather than begining.
• Should read surprisingly rather than suprisingly.
• Should read distinguished rather than distingiushed.
• Should read cursor rather than cusor.

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

[superbobry]

Thanks Tim!