* build: add otp version to elixir in .tool-versions
* refactor: don't make subtree zippers unless needed in `Igniter.Code.Common`
* refactor: internal function in `Igniter.Code.Common`
* docs: add docstring for `Igniter.Code.Common.use_aliases/2`
* refactor: simplify zipper usage
Refactored using these two general rules:
1. Don't make subtrees unnecessarily
zipper
|> Zipper.subtree()
|> Zipper.root()
# is equivalent to
zipper
|> Zipper.node()
2. Access `zipper.node` when appropriate
zipper
|> Zipper.node()
|> case do
...
end
# is equivalent to
case zipper.node do
...
end
* fix: remove redundant case clause in `Igniter.Code.Common`
