Teach Mix erlang compiler alternative spelling for -behavior declaration (#7290)
Teach Mix erlang compiler alternative spelling for -behavior declaration (#7290)

Erlang recognizes both -behaviour and -behavior, but mix was only able to
process one, which made erlang compiler complain about missing behaviour
when source file was using the other one
gfvcastro/elixir,pedrosnk/elixir,elixir-lang/elixir,pedrosnk/elixir,michalmuskala/elixir,kelvinst/elixir,joshprice/elixir,lexmag/elixir,kimshrier/elixir,kimshrier/elixir,gfvcastro/elixir,ggcampinho/elixir,lexmag/elixir,kelvinst/elixir,ggcampinho/elixir