371 - clarify javadoc on config.getConfigSources

Signed-off-by: Emily Jiang <[email protected]>

api/src/main/java/org/eclipse/microprofile/config/Config.java

@@ -273,8 +273,10 @@ default <T> Optional<List<T>> getOptionalValues(String propertyName, Class<T> pr
 
     /**
      * Return all of the currently registered {@linkplain ConfigSource configuration sources} for this configuration.
+     * <p>
      * The returned sources will be sorted by descending ordinal value and name, which can be iterated in a thread-safe manner.
-     *
+     * The {@link java.util.Iterator Iterable} is not alterable and 
+     * contains a fixed number of {@linkplain ConfigSource configuration sources}, which may be either static or dynamic.
      * @return the configuration sources
      */
     Iterable<ConfigSource> getConfigSources();