Add indication about markdown formatting in the publisher
Add expand the publisher test
Merge pull request #4589 from Flaburgan/add-markdown-indication-publisher

[Ready to review] Add indication about markdown formatting in the publisher
#4550: Fix strip HTML when posting
#4550: Added strip_html method
#4550: Removed html tags for each posting service and added specs
#4550: Removed the method from status_message.rb file :)