Provide a normative definition of Attribute (singular) rather than Attributes (plural) (#2123)
Provide a normative definition of Attribute (singular) rather than Attributes (plural) (#2123)

* Provide a normative definition of Attribute (singular)

- Providing a normative definition of **attribute** (singular)
- Other copyedits

/cc @austinlparker @tedsuo

* Move anchor to make markdown checker happy
open-telemetry/opentelemetry-specification,open-telemetry/opentelemetry-specification