Fix broken related posts links

Some of the links didn’t work when published to a subdirectory.

Fix broken page link

v0.5.4

Fix absolute link to post

Fix broken tag link

v0.5.3

Fix absolute link to tag page

Fix broken tag link

v0.5.2

Fix absolute link to tag page

Fix Related Posts heading

v0.5.1

Add id to Related Posts heading

Add support for related posts

v0.5.0

Add support for tags and related posts

Remove double border from quotes within callouts

v0.4.2

Remove border from blockquotes inside callouts

Callout box with better padding

v0.4.1

Fix callout padding for both styles

Add callout box

v0.4.0

Add a callout class for emphasis

Add navigation back to home page

Add navigation back to the home page

This is a rough change, and should be done properly by a UX person
at some point.