Skip tests tagged as document: false on doc gen

When running the below command to re-generate API docs:
RAILS_ENV=test rake docs:generate
it will execute every single rspec test under 'spec/acceptance/**/*_spec.rb'.
It *even* executes the tests that are explicitly marked as:
document: false
With this update, only the rspec tests that contribute to the generation of
API documentation will be executed by default.

Aside: For our team, this reduced the amount of tests being executed during
docs generation down from 195 to 37.

Author: stwr667

lib/tasks/docs.rake

@@ -3,11 +3,11 @@ require 'rspec/core/rake_task'
 desc 'Generate API request documentation from API specs'
 RSpec::Core::RakeTask.new('docs:generate') do |t|
   t.pattern = 'spec/acceptance/**/*_spec.rb'
-  t.rspec_opts = ["--format RspecApiDocumentation::ApiFormatter"]
+  t.rspec_opts = ["--format RspecApiDocumentation::ApiFormatter", "--tag ~@document:false"]
 end
 
 desc 'Generate API request documentation from API specs (ordered)'
 RSpec::Core::RakeTask.new('docs:generate:ordered') do |t|
   t.pattern = 'spec/acceptance/**/*_spec.rb'
-  t.rspec_opts = ["--format RspecApiDocumentation::ApiFormatter", "--order defined"]
+  t.rspec_opts = ["--format RspecApiDocumentation::ApiFormatter", "--tag ~@document:false", "--order defined"]
 end