Fix and add comments to HttpUtil

Motivation:
The comments in HttpUtil need some love.

Modifications
- Update comments in HttpUtil

Result:
Comments are cleaner in HttpUtil.

codec-http/src/main/java/io/netty/handler/codec/http/HttpUtil.java

@@ -50,7 +50,7 @@ public final class HttpUtil {
 
     /**
      * Returns {@code true} if and only if the connection can remain open and
-     * thus 'kept alive'.  This methods respects the value of the
+     * thus 'kept alive'.  This methods respects the value of the.
      * {@code "Connection"} header first and then the return value of
      * {@link HttpVersion#isKeepAliveDefault()}.
      */
@@ -260,6 +260,13 @@ public final class HttpUtil {
         return message.headers().contains(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED, true);
     }
 
+    /**
+     * Set the {@link HttpHeaderNames#TRANSFER_ENCODING} to either include {@link HttpHeaderValues#CHUNKED} if
+     * {@code chunked} is {@code true}, or remove {@link HttpHeaderValues#CHUNKED} if {@code chunked} is {@code false}.
+     * @param m The message which contains the headers to modify.
+     * @param chunked if {@code true} then include {@link HttpHeaderValues#CHUNKED} in the headers. otherwise remove
+     * {@link HttpHeaderValues#CHUNKED} from the headers.
+     */
     public static void setTransferEncodingChunked(HttpMessage m, boolean chunked) {
         if (chunked) {
             m.headers().add(HttpHeaderNames.TRANSFER_ENCODING, HttpHeaderValues.CHUNKED);