Simplify & expand Wait methods, remove FIFO

[clipperhouse]

Addresses #30, read that for justifications. tl;dr a flaky promise is worse than no promise.

Remove the waiter queue, and therefore any FIFO, from the Wait methods.

Clean up now-unused syncMap methods.

…and implement Wait* with details, debugs, and on Limiters. More than planned.

[Copilot]

Pull Request Overview

This PR removes the FIFO (First-In-First-Out) ordering guarantee from the Wait and WaitN methods in the rate limiter library, addressing issue #30. The change simplifies the implementation by eliminating the waiter queue mechanism.

• Remove FIFO ordering guarantees from Wait/WaitN methods
• Delete waiter queue implementation and associated data structures
• Clean up unused syncMap methods that were only needed for waiter management

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
limiter.go	Remove waiters field from Limiter struct
limiter_wait.go	Remove waiter queue logic and FIFO ordering implementation
limiter_wait_test.go	Restructure tests and remove FIFO-specific test cases
syncmap.go	Remove unused syncMap type and associated methods
syncmap_test.go	Remove tests for deleted syncMap functionality