ESLint version

latest

What problem do you want to solve?

clean up and expand Custom Processors page

What do you think is the correct solution?

For Custom Processors page:

add overview to page

• At the top of pages explaining what an extension type is, and why you might want to use it.
  • For example, in the custom formatters documentation, explain why someone might want to create a custom formatter.
• copy edit

Participation

• I am willing to submit a pull request for this change.

Additional comments

No response