[Ruby agent] Update APM language and links

[bmorelli25]

Summary

The APM Server standalone binaries are deprecating in 7.16. Agent documentation needs to be updated to refer to Elastic Agent and the APM integration, and links need to be updated to point to the new APM Guide documentation.

As a part of this issue, the following links need to be fixed:

14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/2.x/api.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/metadata.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/2.x/introduction.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/index.html
14:45:31 INFO:build_docs:   - en/apm/server/7.16/index.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/3.x/api.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/metadata.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/3.x/introduction.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/index.html
14:45:31 INFO:build_docs:   - en/apm/server/7.16/index.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/3.x/log-correlation.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/observability-integrations.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/3.x/upgrading.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/4.x/api.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/metadata.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/4.x/configuration.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/server/7.16/api-key.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/4.x/introduction.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/index.html
14:45:31 INFO:build_docs:   - en/apm/server/7.16/index.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/4.x/log-correlation.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/observability-integrations.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/4.x/upgrading.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/current/api.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/metadata.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/current/configuration.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/server/7.16/api-key.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/current/introduction.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/index.html
14:45:31 INFO:build_docs:   - en/apm/server/7.16/index.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/current/log-correlation.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/observability-integrations.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/current/upgrading.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/master/api.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/metadata.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/master/configuration.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/server/7.16/api-key.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/master/introduction.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/index.html
14:45:31 INFO:build_docs:   - en/apm/server/7.16/index.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/master/log-correlation.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/observability-integrations.html
14:45:31 INFO:build_docs:  /tmp/docsbuild/target_repo/html/en/apm/agent/ruby/master/upgrading.html contains broken links to:
14:45:31 INFO:build_docs:   - en/apm/get-started/7.16/agent-server-compatibility.html

Related

For #1073.

[dedemorton]

Fixed in elastic/apm-agent-ruby#1224