Fix external links in docs

.gitlab/issue_templates/Snowplow event tracking.md

doc/administration/auth/atlassian.md

doc/administration/nfs.md

doc/administration/restart_gitlab.md

doc/administration/troubleshooting/debug.md

doc/administration/troubleshooting/tracing_correlation_id.md

doc/administration/whats-new.md

doc/api/feature_flags.md

doc/api/packages/pypi.md

doc/ci/ci_cd_for_external_repos/github_integration.md

doc/ci/introduction/index.md

doc/ci/runners/configure_runners.md

doc/ci/unit_test_reports.md

doc/ci/yaml/index.md

doc/development/api_graphql_styleguide.md

doc/development/contributing/issue_workflow.md

doc/development/documentation/site_architecture/index.md

doc/development/fe_guide/accessibility.md

doc/development/fe_guide/content_editor.md

doc/development/fe_guide/performance.md