Broken links in the code reported by check-links

We have a bunch of broken links, shouldn't be hard to fix most of them: From https://github.com/open-telemetry/opentelemetry-python-contrib/actions/runs/24585094288/job/71971987631?pr=4461#step:5:835: ``` [✖] https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1670%5D → Status: 404 [✖] https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md → Status: 404 [✖] https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.12.0rc2-0.32b0 → Status: 404 [✖] https://github.com/open-telemetry/opentelemetry-python-contrib/pull/227%5D → Status: 404 [✖] https://github.com/open-telemetryopentelemetry-python-contrib/issues/1033 → Status: 404 ```