Document that the :consolidate_protocols option is true by default (#5091)

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: PragTob

lib/mix/lib/mix/tasks/app.start.ex

@@ -20,7 +20,7 @@ defmodule Mix.Tasks.App.Start do
       applications are started in permanent mode
 
     * `:consolidate_protocols` - when `true`, loads consolidated
-      protocols before start
+      protocols before start. The default value is `true`.
 
     * `:elixir` - matches the current elixir version against the
       given requirement

lib/mix/lib/mix/tasks/compile.ex

@@ -14,7 +14,8 @@ defmodule Mix.Tasks.Compile do
       `[:yecc, :leex, :erlang, :elixir, :xref, :app]`
 
     * `:consolidate_protocols` - when `true`, runs protocol
-      consolidation via the `compile.protocols` task
+      consolidation via the `compile.protocols` task. The default
+      value is `true`.
 
     * `:build_embedded` - when `true`, activates protocol
       consolidation and does not generate symlinks in builds

lib/mix/lib/mix/tasks/compile.protocols.ex

@@ -9,7 +9,8 @@ defmodule Mix.Tasks.Compile.Protocols do
 
   This task is automatically invoked whenever the project
   enables `:consolidate_protocols` or `:build_embedded` in
-  its configuration.
+  its configuration. As `:consolidate_protocols` is enabled
+  in the default configuration, this is the default case.
 
   ## Consolidation