Make it a wrapper

[brunomvsouza]

• Easily verifiable
• Easier to maintain

Important

The upstream lib now requires Go 1.23.

[Copilot]

Pull Request Overview

This PR replaces the custom singleflight implementation with a generic, type‑safe wrapper around the upstream golang.org/x/sync/singleflight package for easier maintenance and verifiability.

• Introduces a wrapper that supports generics with type constraint K ~string.
• Updates go.mod and CI configurations to require Go 1.23 and newer versions of dependencies.
• Removes legacy internal implementation and redundant examples in favor of consolidated usage examples.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
singleflight.go	Replaces custom logic with a generic wrapper and adapts the API.
go.mod	Updates Go version to 1.23.0 and adds required dependency.
examples_test.go	Provides consolidated usage examples.
examples/Forget, examples/DoChan, examples/Do	Remove redundant examples.
README.md	Updates documentation to reflect the new wrapper design.
.github/workflows/ci.yaml	Updates CI workflow for Go 1.24.x/1.23.x and related settings.

Comments suppressed due to low confidence (1)

singleflight.go:44

• The conversion of key to string (using string(key)) relies on the new type constraint (K ~string). Please ensure this design decision is clearly documented so that users understand that only string-like types are accepted.

result, err, shared := g.group.Do(string(key), func() (any, error) {