Update documentation.md (#2356)
Update documentation.md (#2356)

* Update documentation.md

Corrects typos, grammar and suggests format

* Update en/lessons/basics/documentation.md

Co-authored-by: Sean Callan <c88c8e6631c1daa94b541123de8c62a3ca92606f@users.noreply.github.com>
nscyclone/elixir-school,doomspork/elixir_school,doomspork/elixir-school,nscyclone/elixir-school,nscyclone/elixir-school,nscyclone/elixir-school,doomspork/elixir-school,doomspork/elixir_school,doomspork/elixir-school,doomspork/elixir_school