Normalize spelling

Note that "UNIX" is a trademark, "Unix" is not

Author: garydgregory

src/main/java/org/apache/commons/codec/digest/Sha2Crypt.java

@@ -26,7 +26,7 @@
 import java.util.regex.Pattern;
 
 /**
- * SHA2-based UNIX crypt implementation.
+ * SHA2-based Unix crypt implementation.
  * <p>
  * Based on the C implementation released into the Public Domain by Ulrich Drepper &lt;[email protected]&gt;
  * http://www.akkadia.org/drepper/SHA-crypt.txt