add info about available formatters to command line help

Author: dchelimsky

lib/rspec/core/command_line_options.rb

@@ -26,7 +26,9 @@ def parse
             options[:color_enabled] = o
           end
 
-          opts.on('-f', '--formatter [FORMATTER]', 'Choose an optional formatter') do |o|
+          opts.on('-f', '--formatter [FORMATTER]', 'Choose a formatter',
+                  '  [p]rogress (default - dots)',
+                  '  [d]ocumentation (group and example names)') do |o|
             options[:formatter] = o
           end
 

lib/rspec/core/configuration.rb

@@ -54,9 +54,7 @@ def mock_framework=(use_me_to_mock)
 
       def require_mock_framework_adapter
         require case @options[:mock_framework].to_s
-        when ""
-           'rspec/core/mocking/with_rspec'
-        when /rspec/i
+        when "", /rspec/i
           'rspec/core/mocking/with_rspec'
         when /mocha/i
           'rspec/core/mocking/with_mocha'
@@ -130,7 +128,7 @@ def formatter_class
 
       def formatter=(formatter_to_use)
         formatter_class = case formatter_to_use.to_s
-        when /doc/, 's', 'n'
+        when 'd', 'doc', 'documentation', 's', 'n', 'spec', 'nested'
           Rspec::Core::Formatters::DocumentationFormatter
         when 'progress' 
           Rspec::Core::Formatters::ProgressFormatter