Bjørn Erik Pedersen ded74f0982 Add Goldmark as the new default markdown handler
This commit adds the fast and CommonMark compliant Goldmark as the new default markdown handler in Hugo.

If you want to continue using BlackFriday as the default for md/markdown extensions, you can use this configuration:

```toml
[markup]
defaultMarkdownHandler="blackfriday"
```

Fixes #5963
Fixes #1778
Fixes #6355
2019-11-23 14:12:24 +01:00
..
2018-12-24 08:36:16 +01:00