Normalize spelling

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

Author: garydgregory

src/main/java/org/apache/commons/lang3/SystemUtils.java

@@ -1671,7 +1671,7 @@ public class SystemUtils {
     public static final boolean IS_OS_SUN_OS = getOsNameMatches("SunOS");
 
     /**
-     * The constant {@code true} if this is a UNIX like system, as in any of AIX, HP-UX, Irix, Linux, MacOSX, Solaris or SUN OS.
+     * The constant {@code true} if this is a Unix like system, as in any of AIX, HP-UX, Irix, Linux, MacOSX, Solaris or SUN OS.
      *
      * <p>
      * The field will return {@code false} if {@code OS_NAME} is {@code null}.

src/main/java/org/apache/commons/lang3/text/StrBuilder.java

@@ -1150,7 +1150,7 @@ public StrBuilder appendln(final StringBuilder str, final int startIndex, final
      * By default, the new line is the system default from {@link System#lineSeparator()}.
      * </p>
      * <p>
-     * The new line string can be changed using {@link #setNewLineText(String)}. For example, you can use this to force the output to always use UNIX line
+     * The new line string can be changed using {@link #setNewLineText(String)}. For example, you can use this to force the output to always use Unix line
      * endings even when on Windows.
      * </p>
      *