Fix typo ration => ratio in README.md (#198)

Author: jarifibrahim

zstd/README.md

@@ -36,7 +36,7 @@ so as always, testing is recommended.
 For now, a high speed (fastest) and medium-fast (default) compressor has been implemented. 
 
 The "Fastest" compression ratio is roughly equivalent to zstd level 1. 
-The "Default" compression ration is roughly equivalent to zstd level 3 (default).
+The "Default" compression ratio is roughly equivalent to zstd level 3 (default).
 
 In terms of speed, it is typically 2x as fast as the stdlib deflate/gzip in its fastest mode. 
 The compression ratio compared to stdlib is around level 3, but usually 3x as fast.
@@ -390,4 +390,4 @@ For sending files for reproducing errors use a service like [goobox](https://goo
 
 For general feedback and experience reports, feel free to open an issue or write me on [Twitter](https://twitter.com/sh0dan).
 
-This package includes the excellent [`github.com/cespare/xxhash`](https://github.com/cespare/xxhash) package Copyright (c) 2016 Caleb Spare.
+This package includes the excellent [`github.com/cespare/xxhash`](https://github.com/cespare/xxhash) package Copyright (c) 2016 Caleb Spare.