(crystal) Way too many relevance 10s for things found in other languages

[joshgoebel]

@joshgoebel when trying the auto-detect on the developer-playground, the same snippet is considered crystal, which also leads to broken highlighting:

Originally posted by @Hirse in #2921 (comment)

[joshgoebel]

This is because enum scores a 10 when it absolutely should not. At a glance I think all the relevances 10s should simply be removed and returned to the default of 1. enum and union are definitely used by other languages.