8222241: Example in ServiceLoader API docs should have one provides d…

…irective

This patch fixes an example given in the ServiceLoader API doc that, if used, would result in a compilation error.

Reviewed-by: alanb

src/java.base/share/classes/java/util/ServiceLoader.java

@@ -227,10 +227,10 @@
  * the application module path must have a provider constructor. There is no
  * support for a provider method in this case.
  *
- * <p> As an example, suppose a module specifies the following directives:
+ * <p> As an example, suppose a module specifies the following directive:
  * <pre>{@code
- *     provides com.example.CodecFactory with com.example.impl.StandardCodecs;
- *     provides com.example.CodecFactory with com.example.impl.ExtendedCodecsFactory;
+ *     provides com.example.CodecFactory with com.example.impl.StandardCodecs,
+ *              com.example.impl.ExtendedCodecsFactory;
  * }</pre>
  *
  * <p> where