Typo fix and writing style touch-up

[dusandz]

Proposed changes

Documentation update - fixed one typo, and ensured that the spelling of BodyParser matches the one in README, also a couple of style touch-ups.
Changed "parseable" to "parsable", as https://en.wiktionary.org/wiki/parseable favors the latter for formal writing.

Types of changes

• Documentation fix
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have read the CONTRIBUTING doc
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works.
• I have added necessary documentation (if appropriate)

NB: No test-breaking changes were made
NB2: Link referred from CONTRIBUTING https://github.com/adonisjs/adonis-bodyparser/blob/develop/CONTRIBUTING.md leads to 404 page.

[coveralls]

Coverage remained the same at 96.322% when pulling 08d6550 on dusandz:develop into f799b35 on adonisjs:develop.

[RomainLanz]

Thanks 💜