DEV: Add --profile=[COUNT] option for turbo_rspec

Why is this change required?

By default, `RSpec` comes with a `--profile=[COUNT]` option as well but
enabling that option means that the entire test suite needs to be
executed. This does not work so well for `turbo_rspec` which splits our
test files into various "buckets" for the tests to be executed in
multiple processes. Therefore, this commit adds a similar
`--profile=[COUNT]` option to `turbo_rspec` but will only profile the
tests being executed. Examples:

`LOAD_PLUGINS=1 bin/turbo_rspec --profile plugins/*/spec/system`

or

`LOAD_PLUGINS=1 bin/turbo_rspec --profile=20 plugins/*/spec/system`

lib/turbo_tests/documentation_formatter.rb

@@ -1,41 +1,51 @@
 # frozen_string_literal: true
 
-RSpec::Support.require_rspec_core "formatters/base_text_formatter"
-
 module TurboTests
   # An RSpec formatter that prepends the process id to all messages
-  class DocumentationFormatter < RSpec::Core::Formatters::BaseTextFormatter
+  class DocumentationFormatter < ::TurboTests::BaseFormatter
     RSpec::Core::Formatters.register(self, :example_failed, :example_passed, :example_pending)
 
     def example_passed(notification)
       output.puts RSpec::Core::Formatters::ConsoleCodes.wrap(
-                    "[#{notification.example.process_id}] #{notification.example.full_description}",
+                    output_example(notification.example),
                     :success,
                   )
+
       output.flush
     end
 
     def example_pending(notification)
       message = notification.example.execution_result.pending_message
+
       output.puts RSpec::Core::Formatters::ConsoleCodes.wrap(
-                    "[#{notification.example.process_id}] #{notification.example.full_description}" \
-                      " (PENDING: #{message})",
+                    "#{output_example(notification.example)} (PENDING: #{message})",
                     :pending,
                   )
+
       output.flush
     end
 
     def example_failed(notification)
       output.puts RSpec::Core::Formatters::ConsoleCodes.wrap(
-                    "[#{notification.example.process_id}] #{notification.example.full_description}" \
-                      " (FAILED - #{next_failure_index})",
+                    "#{output_example(notification.example)} (FAILED - #{next_failure_index})",
                     :failure,
                   )
+
       output.flush
     end
 
     private
 
+    def output_example(example)
+      output = +"[#{example.process_id}] #{example.full_description}"
+
+      if run_duration_ms = example.metadata[:run_duration_ms]
+        output << " (#{run_duration_ms}ms)"
+      end
+
+      output
+    end
+
     def next_failure_index
       @next_failure_index ||= 0
       @next_failure_index += 1