Update changelog for Objective-C pull request

pmd-objectivec/src/main/java/net/sourceforge/pmd/cpd/ObjectiveCTokenizer.java

@@ -15,8 +15,12 @@ import net.sourceforge.pmd.lang.objectivec.ast.Token;
 
 import org.apache.commons.io.IOUtils;
 
+/**
+ * The Objective-C Tokenizer
+ */
 public class ObjectiveCTokenizer implements Tokenizer {
 
+    @Override
     public void tokenize(SourceCode sourceCode, Tokens tokenEntries) {
         StringBuilder buffer = sourceCode.getCodeBuffer();
         Reader reader = null;

src/site/markdown/overview/changelog.md

@@ -5,6 +5,7 @@
 **New Supported Languages:**
 
 * Matlab (CPD)
+* Objective-C (CPD)
 * Python (CPD)
 
 **Feature Requests and Improvements:**
@@ -15,6 +16,7 @@
 
 * [#11](https://github.com/adangel/pmd/pull/11): Added support for Python to CPD.
 * [#12](https://github.com/adangel/pmd/pull/12): Added support for Matlab to CPD.
+* [#13](https://github.com/adangel/pmd/pull/13): Added support for Objective-C to CPD.
 
 **Bugfixes:**