Apply suggestions from code review

Co-authored-by: Eksperimental <eksperimental@autistici.org>

Author: Papipo

lib/mix/lib/mix/dep.ex

@@ -536,7 +536,7 @@ defmodule Mix.Dep do
   end
 
   @doc """
-  Returns `true` if dependency is a Gleam project.
+  Returns `true` if dependency is a Gleam project; otherwise returns `false`.
   """
   def gleam?(%Mix.Dep{manager: manager}) do
     manager == :gleam

lib/mix/lib/mix/gleam.ex

@@ -72,7 +72,7 @@ defmodule Mix.Gleam do
   defp maybe_erlang_opts(config, opts) do
     application =
       opts
-      |> Enum.filter(fn {_, value} -> value != nil end)
+      |> Enum.reject(fn {_, value} -> value == nil end)
       |> Enum.map(fn
         {"application_start_module", module} when is_binary(module) ->
           {:mod, {String.to_atom(module), []}}