Fix typo in Application start callback doc (#5522)
Fix typo in Application start callback doc (#5522)


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