Doc improvements don’t need a changelog entry.

They just add noise to the changelog.

[ci skip]
describe parameters can now be classes without error
added spec to test new behavior
separate context added for description metadata test
Merge pull request #1636 from nicklink483/fix_metadata_build_description_from

describe parameters can now be classes without error
changelog for #1636
Merge pull request #1616 from rspec/fix_exclusion_priority_for_working_directory

Ignore working directory when excluding system patterns.
changelog for #1616
Address ruby warning.

spec/rspec/core/hooks_spec.rb:197: warning: ambiguous first argument; put parentheses or even spaces
update rake task docs with note about LoadError
Merge pull request #1642 from rspec/update_rake_task_docs

Update rake task docs with note about LoadError