SDL_mixer: Update README-migration.md

From ea22a3085208b6c033e9efc7753d5c271a3fe44c Mon Sep 17 00:00:00 2001
From: Tyler Winters <[EMAIL REDACTED]>
Date: Sat, 25 Apr 2026 09:17:23 -0600
Subject: [PATCH] Update README-migration.md

---
 docs/README-migration.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/README-migration.md b/docs/README-migration.md
index d8cd5353..977e59ec 100644
--- a/docs/README-migration.md
+++ b/docs/README-migration.md
@@ -410,4 +410,6 @@ can discuss it!
 - Mix_GetTimidityCfg => no equivalent in SDL3_mixer.
 - Mix_GetChunk => MIX_GetTrackAudio or MIX_GetTrackAudioStream
 - Mix_CloseAudio => MIX_DestroyMixer
+- Mix_GetError => SDL_GetError
+- Mix_SetError => SDL_SetError