Rust: Add diagnostic query for successfully extracted files.

Author: geoffw0

rust/ql/src/queries/diagnostics/ExtractedFiles.ql

@@ -0,0 +1,13 @@
+/**
+ * @name Extracted files
+ * @description Lists all files in the source code directory that were extracted.
+ * @kind diagnostic
+ * @id rust/diagnostics/successfully-extracted-files
+ * @tags successfully-extracted-files
+ */
+
+import rust
+
+from File f
+where exists(f.getRelativePath())
+select f, "File successfully extracted."