Fixed typos in GenEvent docs. Removed dead link to Getting Started guide.
Fixed typos in GenEvent docs. Removed dead link to Getting Started guide.

pedrosnk/elixir,pedrosnk/elixir,lexmag/elixir,antipax/elixir,gfvcastro/elixir,ggcampinho/elixir,kimshrier/elixir,michalmuskala/elixir,gfvcastro/elixir,antipax/elixir,kelvinst/elixir,joshprice/elixir,beedub/elixir,elixir-lang/elixir,kelvinst/elixir,lexmag/elixir,kimshrier/elixir,beedub/elixir,ggcampinho/elixir