Added tax docs to tax page (#16075)

## DESCRIBE YOUR PR
Add 2026 Portugal and Indonesia PDFs 


https://sentry-docs-git-update-tax-docs.sentry.dev/security-legal-pii/security/tax-documents/

## IS YOUR CHANGE URGENT?  

Help us prioritize incoming PRs by letting us know when the change needs
to go live.
- [x] Urgent deadline (GA date, etc.): ASAP
- [ ] Other deadline: <!-- ENTER DATE HERE -->
- [ ] 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)

Co-authored-by: Shannon Anahata <shannonanahata@gmail.com>

Author: sfanahata

docs/security-legal-pii/security/tax-documents.mdx

@@ -21,9 +21,11 @@ Below you'll find Sentry's tax documents, including the tax residency certificat
 - [India: Electronic _10F_04-2024-to_12-2024](/pdfs/Form-10F_04-2024-to-12-2024_External.pdf)
 - [India: Electronic _10F_01-2024 to_03-2024](/pdfs/Form_10F_Filed_Form_EXTERNAL_01_2024_to_03_2024.pdf)
 - [India: Electronic _10F_04-2023_to_12-2023](/pdfs/India_Electronic_10F_04_2023_to_12_2023.pdf)
+- [Indonesia: Form DGT-1 CY 2026](/pdfs/Indonesdia_Form_DGT_1_CY_2026.pdf)
 - [Indonesia: FORM DGT-1 CY 2025](/pdfs/Indonesdia_form_dgt_1_cy_2025.pdf)
 - [Indonesia: Form DGT-1 CY 2024](/pdfs/Form-DGT-New_Indonesia_FY24_signed.pdf)
 - [Indonesia: Form DGT-1 CY 2023](/pdfs/Form-DGT-New_Indonesia_FY23.pdf)
+- [Portugal: RFI_21_CY 2026](/pdfs/RFI_21_Portugal_Sentry_signed_CY2026.pdf)
 - [Portugal: RFI_21_CY 2025](/pdfs/Portugal_rfi_21_cy_2025.pdf)
 - [Portugal: RFI_21_CY 2024](/pdfs/RFI_21_Portgual_Sentry_signed-FY2024-external.pdf)
 - [Portugal: RFI_21_CY 2023](/pdfs/RFI_21_Portgual_Sentry_signed-FY2023-external.pdf)