error_document (and thus origin_path) shouldn't start with a slash

[forevermatt]

Hi @fillup 👋

terraform-aws-hugo-s3-cloudfront/vars.tf

Lines 110 to 114 in e03a13c

	variable "origin_path" {
	description = "Path in S3 bucket for hosted files, with leading slash"
	type = string
	default = "/public"
	}

These lines state that origin_path should have a leading slash, but I think the README (which says it shouldn't) is actually correct. Including a leading slash seems to break the error_document feature in S3. For example "public/index.html" works as an error document path, but "/public/index.html" doesn't work, and the origin_path is used in assembling the final error document path.

However, changing that expectation for origin_path might require updates to other code in this module.

[fillup]

I'm guessing we always overwrote the default path in our configs, so if we're not using it with the preceding slash it's probably fine to update. Could release as a breaking change revision if we want to make sure not to break things on others using it that way.