String: Rename args "str" to "string"
String: Rename args "str" to "string"

As they were rarely used in the String module.

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