chore(docs): update xendit link

[villebro]

SUMMARY

Fix yet another broken INTHEWILD link.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[rusackas]

Note that the link checker is non-blocking, so it shouldn't prevent merges. Still, appreciating the touchups here!

[villebro]

@rusackas ok, good to know, I thought it was blocking my PR, but maybe there was something else that was blocking it, too.