[Feature Request] Search Tags

[markusa380]

I've recently come across the built-in search functionality shipped with minimal-mistakes and
so far have had a good experience with it.

What I'm looking for now is the ability to define tags for each document (in my case in a collection)
that the search will prioritize, probably as a comma separated list in the front matter.

For example, I have in my wiki a page called United States of America but I would like to be able to come across this document
when searching USA or U.S.A. too, without these words being mentioned explicitly in the text.

This would also allow me to disable full page searching as I could just summarize anything important in the keywords.