spelling fixes in comments

i.e. occurred labeled Huffman
diff --git a/lib/common/threading.h b/lib/common/threading.h
index 74b2ec0..c008613 100644
--- a/lib/common/threading.h
+++ b/lib/common/threading.h
@@ -73,7 +73,7 @@
  */
 
 
-#elif defined(ZSTD_MULTITHREAD)   /* posix assumed ; need a better detection mathod */
+#elif defined(ZSTD_MULTITHREAD)   /* posix assumed ; need a better detection method */
 /* ===   POSIX Systems   === */
 #  include <pthread.h>