(MAINT) Fix README styling
(MAINT) Fix README styling

1. Put spaces after headings so it's more readable in plain text.
2. Set Puppet code type in an example.

fatmcgav/puppetlabs-rabbitmq,rdo-puppet-modules/puppetlabs-rabbitmq,voxpupuli/puppet-rabbitmq,voxpupuli/puppet-rabbitmq,fuel-infra/puppetlabs-rabbitmq,firefly4268/puppetlabs-rabbitmq,fatmcgav/puppetlabs-rabbitmq,acowan/puppetlabs-rabbitmq,synalabs/puppetlabs-rabbitmq,jordanconway/puppetlabs-rabbitmq,DavidS/puppetlabs-rabbitmq,daniel-gadd/puppetlabs-rabbitmq,daniel-gadd/puppetlabs-rabbitmq,puppetlabs/puppetlabs-rabbitmq,Slm0n87/puppet-rabbitmq,rdo-puppet-modules/puppetlabs-rabbitmq,bmjen/puppetlabs-rabbitmq,jordanconway/puppetlabs-rabbitmq,Slm0n87/puppet-rabbitmq,olevole/puppetlabs-rabbitmq,firefly4268/puppetlabs-rabbitmq,jaxxstorm/puppetlabs-rabbitmq,jaxxstorm/puppetlabs-rabbitmq,Slm0n87/puppet-rabbitmq,optiz0r/puppetlabs-rabbitmq,optiz0r/puppetlabs-rabbitmq,olevole/puppetlabs-rabbitmq,acowan/puppetlabs-rabbitmq,bmjen/puppetlabs-rabbitmq,gizmoguy/puppet-rabbitmq,plumgrid/puppetlabs-rabbitmq,gizmoguy/puppet-rabbitmq,DavidS/puppetlabs-rabbitmq,synalabs/puppetlabs-rabbitmq,fuel-infra/puppetlabs-rabbitmq,plumgrid/puppetlabs-rabbitmq,puppetlabs/puppetlabs-rabbitmq