Add option to not try inserting a heading if it's missing

[smixqse]

I'm currently having a conflict with Templater folder templates and I think this could be easily solved by having an option to not try inserting a heading if it's missing.

I don't think I will need the plugin to auto-insert the heading if I always use templates, so I think this could be a useful workaround for that problem and a good feature overall.