The goal is to add a behat test to verify that forum posts can display the word count

QA test to be automated: MDLQA-5265

QA testing instructions

1. As a teacher in a course, create a standard forum and set "Display word count" to Yes
2. Add a new discussion topic; type some words and save.
3. Verify the word count is displayed correctly.
4. Create a forum of the "single simple discussion" type and in the "Attachments and word count", enable the word count.
5. Add some text and save.
6. Verify the word count is displayed correctly.
7. As a teacher create a forum of the "each person posts one discussion" type and set "Display word count" to Yes
8. Add some text and save.
9. Verify the word count is displayed correctly.
10. Create a forum of the "Q and A" type and set "Display word count" to Yes
11. Add a new question; type in some text and save.
12. Verify the word count is displayed correctly.
13. Create a new forum of the "blog-like format" type and set "Display word count" to Yes
14. Add a new topic; type some words and save.
15. Verify the word count is displayed correctly.