"Suggest an Edit" link in post metadata

[SeanKilleen]

I've gotten enough positive feedback about this that I thought it might make sense to contribute it back to the theme.

On all of my posts, I have a Suggest an Edit link in the post metadata that goes to the github edit page for the blog.

It allows an override for page.edit_link (in cases where you may want to point readers to a YAML file in _data for example), and if the edit link is enabled, it assigns the edit link and shows it.

{% if page.edit_link %}
  {% assign edit_link = page.edit_link %}
{% else %}
  {% assign edit_link = "https://github.com/" | append: site.repository | append: "/edit/" | append: site.defaultbranch | append: "/" | append: page.path %}
{% endif %}

I then update post__meta to include the edit link.

It's a little naive at the moment, but if there's interest I'd be happy to mature it a bit and contribute it back.

@mmistakes let me know if you're interested in this (no offense if you're not 👍 ).