Whitespace.
Fix specialist tag validation.

Tag slugs should only be allowed to contain a
slash if they're a child tag.
Merge pull request #161 from alphagov/fix-specialist-tag-validation

Fix specialist tag validation
Fix tag validation.

Tags slugs may only contain `/` if they're a child
tag.
Making related_items a scope so it can be chained

removing the existing method and comment because
it is misleading. it says the method is uses only
in Panopticon, but there are usages outside as well.
one of the usages in Panopticon have been removed.
Merge pull request #163 from alphagov/enable-related-artefacts

Making related_items a scope so it can be chained
Release 10.4.2

Making Artefact.relatable_items a scope so that it can be chained.
Add artefact kind for manuals
Add ManualEdition