schemadoc: Render view query in schema documentation

Created by: eseliger

I find it very hard to see what changed when someone has a migration that recreates a view, because the git diff will just be all new lines. This implements adding the backing query to the generated schema file, which should make it easier to discover what actually changed in a migration that touches views.

Created by: sourcegraph-bot

Notifying subscribers in CODENOTIFY files for diff 6c29d5b23c30c3304c3c1614cfdf3ad927735772...3ae8fd575c4d800a51e931d99bbded68ab7dee4b.

Notify	File(s)
@efritz	internal/database/schemadoc/main.go