Describe the bug
(*Tree).SetPath() doesn't set the values of all the paths if toml contains array of tables.

To Reproduce

    config := `
	[[inputs.nginx]]
		urls = ["http://127.0.0.1:9090/nginx_status"]
		response_timeout = '5s'
		[inputs.nginx.tags]
		newmetric1 = "insights1"
	
	[[inputs.nginx]]
		urls = ["http://127.0.0.1:9090/nginx_status"]
		response_timeout = '5s

I've recently come to realize that the 'one-size-fits-all' mega-snippets on marzer.github.io/tomlplusplus aren't necessarily useful for everyone, and I should break them up into smaller sub-examples. I'd be totally happy to accept help with this, though that may be wishful thinking!