Fix spelling mistake

Author: jfreilly

src/BZip2/BZip2Constants.cs

@@ -100,7 +100,7 @@ internal sealed class BZip2Constants
 
 		/// <summary>
 		/// When multiplied by compression parameter (1-9) gives the block size for compression
-		/// 9 gives the best compresssion but uses the most memory.
+		/// 9 gives the best compression but uses the most memory.
 		/// </summary>		
 		public const int BaseBlockSize = 100000;