MINOR: Fix VariantUtil.getByte() Javadoc copied from getShort() (apache#3649)

The Javadoc on the package-private VariantUtil.getByte() was copied
verbatim from getShort() and never adjusted. It listed SHORT as a
supported type and documented an @return of "short value", but the
method only accepts the BYTE/INT8 type and returns a byte.

Correct the doc to describe Type.BYTE and an @return of "The byte
value". No behavioral change.

Signed-off-by: Anas Khan <83116240+anxkhn@users.noreply.github.com>

Author: anxkhn

parquet-variant/src/main/java/org/apache/parquet/variant/VariantUtil.java

@@ -546,9 +546,9 @@ static short getShort(ByteBuffer value) {
   }
 
   /**
-   * Similar to getLong(), but for the types: Type.BYTE, SHORT.
+   * Similar to getLong(), but for the type: Type.BYTE.
    * @param value The Variant value
-   * @return The short value
+   * @return The byte value
    */
   static byte getByte(ByteBuffer value) {
     checkIndex(value.position(), value.limit());