Support github bold markdown flavor

[thienlnam]

Fixed Issues

$ GH_LINK

Tests

1. What unit/integration tests cover your change? What autoQA tests cover your change?
2. What tests did you perform that validates your changed worked?

QA

1. What does QA need to do to validate your changes?
2. What areas to they need to test for regressions?

[thienlnam]

Closing as it seems like there is some handling with mentions / rooms that have a certain expectation. Going to just update the markdown from the backend