Document contents of headerMap

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1522870 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/csv/CSVParser.java

@@ -197,6 +197,8 @@ public final class CSVParser implements Iterable<CSVRecord>, Closeable {
     // the following objects are shared to reduce garbage
 
     private final CSVFormat format;
+
+    /** A mapping of column names to column indices */
     private final Map<String, Integer> headerMap;
 
     private final Lexer lexer;