`red carpet` won't install on jruby.
Fix spec that was failing on jruby.

On jruby, the error for calling an undefined method
is a bit inconsistent:

The first time:

"undefined method `abcd' for #<#<Class:0x3cdb8522>:0x70019a64>"

The second time:

"undefined local variable or method `abcd' for #<#<Class:0x3cdb8522>:0x70019a64>"
Merge pull request #499 from rspec/fix-jruby-builds

Fix jruby builds
Update the documentation to use the new expectation syntax.

* Update cukes to use the new expectation syntax where possible.
* Update RDoc documentation to use the `expect` syntax where applicable.
* Add RDoc documentation for `syntax=` & `syntax` methods.
* Rename cukes to reflect new syntax.