Check command global

[marcusklaas]

This is take two of #663. Instead of checking links at a page level, they are all gathered and then checked asynchronously.

Testing this was hard. I replaced the site level tests by a test ensuring that the right links are collected, but wasn't quite sure how to do the link check testing at a site level. Would be very grateful for any pointers in this area!

Dead link errors look this now:

marcusklaas@localhost ~/fully_faithful_eu> zola check
Checking site...
Failed to check the site
Error: Dead link in /home/marcusklaas/fully_faithful_eu/content/fantasy-league-data.md to ../fantasy-league-introduction: relative URL without a base
Dead link in /home/marcusklaas/fully_faithful_eu/content/pulldown-cmark.md to https://githudb.com/raphlinus/pulldown-cmark: error trying to connect

Doing a site check takes 2.8 seconds compared to a 7.5 second site build on zola 0.6.

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[marcusklaas]

Oh, and syntax highlighting is now disabled for the check command!

[Keats]

The code itself looks good!

The only thing is that I'm thinking it should be enhanced to check for the internal links (with anchors)/relative links as well. There is an upcoming change to internal links (#686), I'll update this PR myself afterwards if necessary

[Keats]

I'm not sure how to test that either to be honest :/ I have seen a couple of things to change after trying it locally but no need to hold up the merge

[Keats]

The only thing is that it looks like you forgot to push a commit formatting the output to the console? It doesn't have the link and the uses {:?} for the result.

[marcusklaas]

You're absolutely right. I forgot to push that commit. I'll open a new PR for it.