Update db-active-record.md

Minor syntax changes.
Fixed broken links [skip ci]
Update concept-components.md

Removed unnecessary comma.
Update concept-properties.md

Minor syntax changes
Update concept-events.md

Minor syntax changes.
Update concept-behaviors.md

Minor syntax changes.
Update concept-service-locator.md

Minor syntax changes.
Update concept-autoloading.md

Minor syntax changes.
Update concept-configurations.md