refactor dynamic_forms.js to be more intuitive (no token)

[simonLeary42]

parseMinMaxFor uses the variable name tokens to describe regex match groups, but I think that's confusing since the word "token" already has a special meaning in this file. So I changed it to groups.

makeChangeHandlers uses the variable name token to describe a substring of an option-for directive, but I think that's confusing because it contains other characters as well as the token.

[simonLeary42]

I reverted the function name changes, and I broke off #5146 and #5145 into separate PRs.

[johrstrom]

Yea I'm not so sure on this one, "token(s)" generally mean "thing(s) you've parsed" which I think fits here as we're parsing these values from javascript data fields.

Indeed you're passing the variable to idFromToken suggesting that the thing you're passing is a 'token' (something you've parsed from another string).

[simonLeary42]

👍