WriteFreely ActivityPub mentions testing

Trying out ActivityPub mentions which are available since v0.12.0rc1.

Should be using gollowing handles:

My name is Gytis Repečka, I am Solution Architect and data professional. I enjoy using, promoting and contributing to open source software and love communicating about tech to both advanced and non-tech people. Visit Inretio for consulting services. Comment by mentioning me @gytisrepecka@social.gyt.is on Fediverse.