Use 1.8.7 compatible ruby syntax.
Satisfy rubocop.

Offenses:

lib/rspec/core/example.rb:418:11: C: Do not prefix reader method names with get_.
      def get_generated_description
          ^^^^^^^^^^^^^^^^^^^^^^^^^
lib/rspec/core/example.rb:421:131: C: Line is too long. [139/130]
        location_description + " (Got an error when generating description from matcher: #{e.class}: #{e.message} -- #{e.backtrace.first})"
                                                                                                                                  ^^^^^^^^^
Fix invalid YARD method reference.

[warn]: In file `lib/rspec/core/formatters/protocol.rb':3: Cannot resolve link to #dump_failure from text:
[warn]: ...{#dump_failure}...
Fix YARD warnings.

[warn]: In file `lib/rspec/core/rake_task.rb':29: Cannot resolve link to ,// from text:
[warn]: ...{,//}...
[warn]: In file `lib/rspec/core/rake_task.rb':29: Cannot resolve link to ,// from text:
[warn]: ...{,//}...

Note that I haven't been able to repro these warnings locally with YARD
but they happen on travis. While I was at it, I fixed up some
inaccuracies in the documented defaults for rake task options.