Add Discarded Hash to list of filters on stats page (#13115)

<!-- Use this checklist to make sure your PR is ready for merge. You may
delete any sections you don't need. -->

## DESCRIBE YOUR PR

Closes #13092

## IS YOUR CHANGE URGENT?  

Help us prioritize incoming PRs by letting us know when the change needs
to go live.
- [ ] Urgent deadline (GA date, etc.): <!-- ENTER DATE HERE -->
- [ ] Other deadline: <!-- ENTER DATE HERE -->
- [x] None: Not urgent, can wait up to 1 week+

## SLA

- Teamwork makes the dream work, so please add a reviewer to your PRs.
- Please give the docs team up to 1 week to review your PR unless you've
added an urgent due date to it.
Thanks in advance for your help!

## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [ ] Checked Vercel preview for correctness, including links
- [ ] PR was reviewed and approved by any necessary SMEs (subject matter
experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs
team](https://github.com/orgs/getsentry/teams/docs)

## LEGAL BOILERPLATE

<!-- Sentry employees and contractors can delete or ignore this section.
-->

Look, I get it. The entity doing business as "Sentry" was incorporated
in the State of Delaware in 2015 as Functional Software, Inc. and is
gonna need some rights from me in order to utilize my contributions in
this here PR. So here's the deal: I retain all rights, title and
interest in and to my contributions, and by keeping this boilerplate
intact I confirm that Sentry can use, modify, copy, and redistribute my
contributions, under Sentry's choice of terms.

## EXTRA RESOURCES

- [Sentry Docs contributor guide](https://docs.sentry.io/contributing/)

Co-authored-by: Alex Krawiec <[email protected]>

Author: coolguyzone

docs/product/stats/index.mdx

@@ -34,6 +34,7 @@ Filtered events and attachments intentionally excluded based on defined settings
 
 - **Browser Extensions**: Filtered by browser extension.
 - **Chunk Load Errors**: Filtered when code chunks can’t be found on the server.
+- **Discarded Hash**: Filtered based on fingerprints of previously deleted and discarded issues.
 - **Error Message**: Filtered based on specific error messages.
 - **Filtered Transaction**: Filtered because it was a call to a filtered transaction.
 - **Invalid CSP**: Filtered due to an invalid Content Security Policy (CSP) policy.