Promote on https://pre-commit.com/hooks.html

[hukkin]

We should make a PR here https://github.com/pre-commit/pre-commit.com to make scss-compile appear on https://pre-commit.com/hooks.html

[chrisjsewell]

Yep cheers, just "solidifying" it a bit, and also there's a bit of an open question about how it interacts with PR merging (executablebooks/sphinx-panels#32 (comment))