Say I load a .txt file into Vim. Then I want to change the filetype=html but I also want an associated ftplugin loaded. How can I do this? I've tried stuff like: :set filetype plugin on and :set filtype plugin_name on and also :filetype plugin_name on etc etc., but I can't seem to manually load the ftplugin. Any suggestions?
I've tried :filetype=html and then :filetype plugin on and other combinations to no avail.
EDIT: I was not able to "completely" solve this with any of the answers (but it maybe something individual to my configuration). However, Pierre's answers were pretty darn good so I'm giving him the green checkmark.