[receiver/tcp_check] rename to tcp_check with deprecated alias tcpcheck

[nicknikolakakis]

Part of:

• Rename components to match naming convention #45339

Description

Renames the tcpcheck receiver type to tcp_check to match the snake_case naming convention established in open-telemetry/opentelemetry-collector#14208.

The previous type tcpcheck is preserved as a deprecated alias via xreceiver.WithDeprecatedTypeAlias, so existing user configurations remain functional and will log a deprecation warning at startup.

Metric names (tcpcheck.*) and the directory layout (receiver/tcpcheckreceiver) are intentionally unchanged to avoid user-facing breakage, matching the precedent set by other receiver renames under #45339 (e.g. #47505, #47369, #47370, #47291, #46750, #46729).

Link to tracking issue

Part of #45339

Testing

• make generate regenerates internal/metadata/generated_status.go, generated_component_test.go, internal/metadata/config.schema.yaml, internal/metadata/generated_config.go, and documentation.md with the new type
• go test ./... passes for the receiver (including TestLoadConfig/tcp_check after updating testdata/config.yaml)
• make lint passes for the receiver
• make chlog-validate passes
• make gendistributions and make generate-chloggen-components produced the same diff as my edits

Documentation

• Added a note at the top of the Configuration section in README.md explaining the rename and that the deprecated alias is still accepted
• Updated the example config in README.md to use tcp_check:
• Updated testdata/config.yaml to use the new receiver key

[codeboten]

please resolve the conflicts so we can get this merged

[nicknikolakakis]

done.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[otelbot]

Thank you for your contribution @nicknikolakakis! 🎉 We would like to hear from you about your experience contributing to OpenTelemetry by taking a few minutes to fill out this survey. If you are getting started contributing, you can also join the CNCF Slack channel #opentelemetry-new-contributors to ask for guidance and get help.