docs: Fix a few typos

[timgates42]

There are small typos in:

• README.rst
• docs/source/index.rst

Fixes:

• Should read verifying rather than veririfying.
• Should read separately rather than seperately.
• Should read respective rather than repsective.
• Should read receiving rather than receving.
• Should read receive rather than recieve.
• Should read encrypted rather than encypted.
• Should read encrypted rather than enctypted.

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