Docs: Omit multi-threaded decompress from TODO.

The TODO file outdated still.
2022-12-12 15:31:14 +02:00 · 2022-12-12 15:31:14 +02:00 · f2d98e6910
--- a/2
+++ b/2
@ -59,8 +59,6 @@ Missing features
      - Implement threaded match finders.
      - Implement pigz-style threading in LZMA2.

-    Multithreaded decompression
-
    Buffer-to-buffer coding could use less RAM (especially when
    decompressing LZMA1 or LZMA2).