horror_(expression) -> horrified

BUR #4395 has been approved by @evazion.

create alias horror_(expression) -> horrified

All of the other tags representing emotions are adjectives used to attribute that emotion to someone, not the nouns that name the emotion itself: happy rather than happiness, sad rather than sadness, depressed rather than depression, embarrassed rather than embarrassment, scared rather than fear, etc. It would be more consistent for horrified to be the primary name of that tag currently called horror_(expression), and also remove its reliance on a qualifier to be distinguishable from horror_(theme).

I think it might be better to consider using a different term. Horrify/horrified is ambiguous and can mean either to fill with terror (ie terrify) or to shock. If the tag is specifically for having depictions of a character filled with terror, then it would be better to name it terrified.

I'm not sure "terrified" is the word I'd use for expressions like post #3871685. I'd rather keep horrified to cover it.

The wiki should be updated then to include examples and a more clear cut definition, because as it currently stands it it is rather ambiguous and posts under the tag currently reflect that ambiguity (like post #3597335 vs post #3619970 vs post #2262950).

The bulk update request #4395 (forum #178722) has been approved by @evazion.