`jinja2-mode` shouldn't inherit from `html-mode`

[zzantares]

Hey, recently I experienced a weird behavior when auto-formatting jinja2-mode buffers (see https://github.com/radian-software/apheleia/issues/220) that was solved simply by disabling the formatter, however, since I was using it for editing Ansible templates, specifically for editing systemd's unit files it got me thinking that these files shouldn't be detected as HTML since Jinja could work for any kind of file, so if may I suggest, jinja shouldn't inherit from HTML, that is (derived-mode-p 'html-mode) for jinja buffers should be nil.