Previous implementation was returning everything in a single Vector,
when what we really want is a Vector of Vectors, one for each comma-
separated part of the list.
This is very much stubbed out for now. Most notably is
Parser::convert_rule() where most of the conversion will happen
from the parser's internal rule classes to CSSRule and its children.
Previously these were all passed around by value, but some of them
(StyleComponentValueRule and StyleBlockRule) want to include each
other as fields, so this had to change.
We had some inconsistencies before:
- Sometimes "The", sometimes "the"
- Sometimes trailing ".", sometimes no trailing "."
I picked the most common one (lowecase "the", trailing ".") and applied
it to all copyright headers.
By using the exact same string everywhere we can ensure nothing gets
missed during a global search (and replace), and that these
inconsistencies are not spread any further (as copyright headers are
commonly copied to new files).
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
