Executable.find does not always correctly detect when to use `bundle exec …`

[noniq]

This comment correctly describes the actual behaviour correctly:

https://github.com/textmate/ruby.tmbundle/blob/74713556df10fbc7b1f9e99013ab1e34cd836f56/Support/lib/executable.rb#L39-L40

But in the case of RSpec (for example), there is no gem named rspec: The binary is part of rspec-core instead.

So currently using Executable.find('rspec') will never return bundle exec rspec. I’ll have to think a bit about how to fix this.