Auto merge of #14410 - canaltinova:stylo-things, r=Manishearth

Implement 3 more properties for stylo

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Implemented these new properties:

1. Implemented parsing/serialization and stylo glue for `background-blend-mode`.
2. Made `align-items` work for stylo.
3. Implemented parsing/serialization for `-moz-column-rule`.

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

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- [X] These changes do not require tests because it's stylo changes.

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