Updated article: Normalization in HTML and CSS

The article Normalization in HTML and CSS was largely rewritten. It now describes the various normalization forms, and clarifies that W3C doesn’t require all content to be strictly NFC-normalized. It also warns about the dangers of blindly normalizing content to a particular normalization form (unless performing a match/sort procedure).

Translators are invited to update the translations in German, Spanish, French, Polish, Brazilian Portuguese, Russian, and Ukrainian.