Processor doc: add description for queued retry processor (#454)
Processor doc: add description for queued retry processor (#454)

Signed-off-by: Hui Kang <06099befa36bf5a07a5196d8e1177abdf1d958ba@us.ibm.com>
open-telemetry/opentelemetry-collector-contrib,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector,open-telemetry/opentelemetry-collector-contrib