This is a mid-size refactor that affects several validators.
Most prominently, the ones that had an `$identical` parameter
to deal with case sensitiveness.
This parameter was confusing, effectively making validators such
as `Contains` behave very differently for arrays versus strings.
In arrays, `$identical` meant "the same type", while it in strings
it meant "case sensitive".
That parameter was removed, and the default behavior is now to
always compare **case sensitive** and strict typing.
A document explaining how to combine other validators in order
to achieve case _insensitive_ comparisons was added.
Additionally, the `Call` validator was refactored back to be
suitable to take on the task of being a fast, quick composable
validator.
With the introduction of `Circuit`, we can shift the responsibility
of dealing with possible mismatches to the user. This kind of type
handling is demonstrated in how I refactored `Tld` to account for
the type mismatch without setting error handlers.
This commit introduces REUSE compliance by annotating all files
with SPDX information and placing the reused licences in the
LICENSES folder.
We additionally removed the docheader tool which is made obsolete
by this change.
The main LICENSE and copyright text of the project is now not under
my personal name anymore, and it belongs to "The Respect Project
Contributors" instead.
This change restores author names to several files, giving the
appropriate attribution for contributions.
This validator is similar to Contains, but also checks how many
times the needle appears.
Additionally, the Domain validator was changed to use it instead
of relying on an unserializable callback, thus, making it
serializable.
