LibCompress: Move finishing the current XZ block into its own function

Author: https://github.com/timschumi
Commit: 68984abc43
Pull-request: https://github.com/SerenityOS/serenity/pull/18193
Reviewed-by: https://github.com/bgianfo ✅

Userland/Libraries/LibCompress/Xz.h

@@ -112,6 +112,7 @@ private:
     XzDecompressor(NonnullOwnPtr<CountingStream>);
 
     ErrorOr<bool> load_next_stream();
+    ErrorOr<void> finish_current_block();
 
     NonnullOwnPtr<CountingStream> m_stream;
     Optional<XzStreamFlags> m_stream_flags;