Change rake tasks to improve formatting

tasks/console.rake

@@ -1,11 +1,13 @@
 # frozen_string_literal: true
 
-desc "Load gem inside irb console"
+desc "Load gem inside IRB console"
 task :console do
   require "irb"
   require "irb/completion"
   require_relative "../lib/tty-screen"
   ARGV.clear
   IRB.start
 end
-task :c => :console
+
+desc "Alias for the :console task"
+task c: :console

tasks/spec.rake

@@ -24,11 +24,11 @@ begin
       task.pattern = "spec/perf{,/*/**}/*_spec.rb"
     end
   end
-
 rescue LoadError
   %w[spec spec:unit spec:integration spec:perf].each do |name|
+    desc "Run #{name == "spec" ? "all" : name.split(":").last} specs"
     task name do
-      $stderr.puts "In order to run #{name}, do `gem install rspec`"
+      warn "In order to run #{name}, do `gem install rspec`"
     end
   end
 end