Print existing steps and step definitions

### 🤔 What's the problem you're trying to solve?

Get a list of all step definitions and steps that match these step definitions.

### ✨ What's your proposed solution?

List all the steps and step definitions:

npx @cucumber/language-server --list

* I have {int} cuke(s) # features/step_definitions/foo.ts:43
* I have 3 cukes # features/a.feature:32
* I have 1 cuke # features/b.feature:12
* /I eat (\d+) cukes/ # features/step_definitions/foo.ts:15
* I eat 3 cukes # features/a.feature:11

### ⛏ Have you considered any alternatives or workarounds?

This is implemented in the `usage` formatter in various Cucumber implementations. By implementing it here we can remove this from all Cucumbers.