Fix acronym case

Author: garydgregory

src/main/java/org/apache/commons/compress/archivers/tar/TarArchiveStructSparse.java

@@ -21,7 +21,7 @@
 import java.util.Objects;
 
 /**
- * A {@code struct sparse} in a <a href="https://www.gnu.org/software/tar/manual/html_node/Standard.html">Tar archive</a>.
+ * A {@code struct sparse} in a <a href="https://www.gnu.org/software/tar/manual/html_node/Standard.html">TAR archive</a>.
  * <p>
  * Whereas, "struct sparse" is:
  * </p>