Time spent in the 'find module with suffix' portion of our `customResolve` function were adding up to around 100ms-150ms when booting the app. This time is spread over 150+ calls, so it's not immediately obvious in flamegraphs.
This commit implements a (reversed) [Trie](https://en.wikipedia.org/wiki/Trie) which enables fast suffix-based lookups on a list of strings.
In my tests, this requires < 5ms to initialize, and brings the cumulative 'find module with suffix' time down to `< 5ms`. This corresponds to a ~100ms improvement in LCP metrics in my browser.
The only behavior change is to remove support for module filenames which are **not** dasherized. I haven't found any core/theme/plugin modules which are not dasherized in their filenames.
