fix: Remove garbage "hash-source" path from content

Previously, when this was used as a flake, the src/content/wiki directory
was as empty folder. This meant that the nix script would move the
content in, keeping the source folder name intact

By moving the content of the folder, we can mitigate this issue no matter
whether the folder was pre-existing

nix/packages/docs-site/default.nix

@@ -19,8 +19,8 @@ buildNpmPackage {
   npmFlags = [ "--ignore-scripts" ];
 
   postUnpack = ''
-    mkdir -p $sourceRoot/src/content
-    cp -r ${inputs.wiki} $sourceRoot/src/content/wiki
+    mkdir -p $sourceRoot/src/content/wiki
+    cp -r ${inputs.wiki}/* $sourceRoot/src/content/wiki
   '';
 
   installPhase = ''