docs: name the registries behind assets and dedup

The guides said files over 50 MB become release assets and that RPG Maker and ScummVM were the trees kept out of dedup. .gitignore decides the first, four committed files are over 50 MB, and NODEDUP_DIRS holds eleven trees.

wiki/troubleshooting.md

@@ -154,7 +154,7 @@ in [verification modes](verification-modes.md#severity-matrix).
 Focus on CRITICAL issues first. WARNING files improve the experience but aren't
 strictly necessary. INFO files are nice to have.
 
-**Large files (over 50 MB):**
+**Large files (release assets):**
 
 Files like PS3UPDAT.PUP, PSVUPDAT.PUP, and Switch firmware are too large for the
 git repository. They are stored as GitHub release assets under the `large-files`