fix spellings and grammar typo in string module
fix spellings and grammar typo in string module

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