Make from in TokenList.slice(from, to) inclusive

[marcelocenerine]

TokenList.slice(from, to) doesn't have the same behavior as slice in the Scala's std collection. This is due to the fact that the from parameter is exclusive. This is something that rule authors may not expect and can be the cause of bugs for those not familiar with the implementation details of TokenList.

The current behavior also affects usability. For instance, while removing tokens what could take a single step (ctx.removeTokens(tokenList.slice(tk, last)) actually requires 2 (ctx.removeToken(tk) + ctx.removeTokens(tokenList.slice(tk, last)).

See https://github.com/scalacenter/scalafix/pull/474/files#r157779985