Stop Mediawiki tinymce editor to convert html code

I'm just started to working with mediawiki file. I installed Bootstrap extension there and added jquery also. Everything was fine but In tinymce editor when i use html tag like , after submit it's just vanished that tag & left only plain text. I searched similar issue since 2 days on internet but can't find solution that work for me. I've tried html entities, cleanup, valid_elements and many more things. Is there any solution ?

any suggestions will be appreciated. Ask me if you want to see something.

source https://stackoverflow.com/questions/67761425/stop-mediawiki-tinymce-editor-to-convert-html-code