format: Refactor wildcard names to rewrite early

Instead of playing games with trying to format them nicely, we instead
can just rewrite them right at the start to no longer be wildcards if
they show up >1 time in the policy.

This fixes a panic being caused if a ref had an array path segment, by
making a new term we were passing along a nil Location. While we could
correct this by just passing the original term from the ref we can
avoid all this special handling altogether by rewriting the wildcards
earlier.

Fixes: #2430
Signed-off-by: Patrick East <east.patrick@gmail.com>