Improve Operators Documentation Page

Description

This is an issue that is reserved for the Airflow Summit "Contributors" Workshop. This is denoted with the label contributors-workshop. Out of respect for the organizers and participants of this workshop, please do not implement a PR that addresses this issue.

If this issue is still open following Airflow Summit, the label will be removed and the issue can be picked up.

There are a couple of areas where the Operators documentation can be improved:

• Handful of typos/capitalization issues (at least one under Reserved params keyword)
• Link to pre/post-execute documentation or include enhanced docs

Link to docs: https://airflow.apache.org/docs/apache-airflow/stable/core-concepts/operators.html

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct