Update umbrella-projects.md (#2093)
Update umbrella-projects.md (#2093)

Some stylistic improvements of the German translation
doomspork/elixir_school,nscyclone/elixir-school,nscyclone/elixir-school,nscyclone/elixir-school,doomspork/elixir-school,doomspork/elixir_school,doomspork/elixir_school,doomspork/elixir-school,nscyclone/elixir-school,doomspork/elixir-school