Clarify codepoint vs. grapheme in String docs
Clarify codepoint vs. grapheme in String docs

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