Add cross-reference for Context Dictionary (#14428)
Add cross-reference for Context Dictionary (#14428)

https://github.com/apache/airflow/issues/14396#issuecomment-785250252

Many users don't know what they can use in the context dictionary,
hopefully this will help.
cfei18/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,Acehaidrey/incubator-airflow,nathanielvarona/airflow,cfei18/incubator-airflow,lyft/incubator-airflow,lyft/incubator-airflow,mistercrunch/airflow,danielvdende/incubator-airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,dhuang/incubator-airflow,apache/incubator-airflow,bolkedebruin/airflow,cfei18/incubator-airflow,sekikn/incubator-airflow,danielvdende/incubator-airflow,mistercrunch/airflow,dhuang/incubator-airflow,nathanielvarona/airflow,mistercrunch/airflow,nathanielvarona/airflow,danielvdende/incubator-airflow,bolkedebruin/airflow,Acehaidrey/incubator-airflow,apache/airflow,bolkedebruin/airflow,lyft/incubator-airflow,dhuang/incubator-airflow,Acehaidrey/incubator-airflow,Acehaidrey/incubator-airflow,dhuang/incubator-airflow,apache/airflow,danielvdende/incubator-airflow,danielvdende/incubator-airflow,mistercrunch/airflow,bolkedebruin/airflow,sekikn/incubator-airflow,apache/incubator-airflow,apache/airflow,cfei18/incubator-airflow,danielvdende/incubator-airflow,nathanielvarona/airflow,apache/airflow,apache/incubator-airflow,apache/airflow,nathanielvarona/airflow,cfei18/incubator-airflow,cfei18/incubator-airflow,nathanielvarona/airflow,apache/airflow,sekikn/incubator-airflow,sekikn/incubator-airflow,lyft/incubator-airflow