Fixed documentation typo. (#181)

Co-authored-by: Shawn <[email protected]>

tutorials/lessons/lesson_06_plugin_dependencies/src/main/java/gov/hhs/aspr/ms/gcm/lessons/Example_6.java

@@ -17,7 +17,7 @@ private Example_6() {
  /*
  * start code_ref=plugin_dependencies_connecting_the_plugins|code_cap=The
  * people, vaccine, family and model plugins are contributed to the simulation.
- * On execution, the model pluin's single actor schedules the vaccination of
+ * On execution, the model plugin's single actor schedules the vaccination of
  * each person as well as a few random removals of people from the simulation.
  */
  public static void main(String[] args) {