checkstyle.xml: add 3 modules

Author: stephengold

config/checkstyle/checkstyle.xml

@@ -61,6 +61,8 @@
             <property name="id" value="AnnotationLocationVariables"/>
             <property name="tokens" value="VARIABLE_DEF"/>
         </module>
+        <module name="AnnotationUseStyle"/>
+        <module name="MissingDeprecated"/>
 
         <!-- Checks for blocks:                       -->
         <!-- See https://checkstyle.org/checks/blocks -->
@@ -104,6 +106,7 @@
         <!-- See https://checkstyle.org/checks/coding -->
         <module name="AvoidDoubleBraceInitialization"/>
         <module name="AvoidNoArgumentSuperConstructorCall"/>
+        <module name="CovariantEquals"/>
         <module name="DefaultComesLast"/>
         <module name="EmptyStatement"/>
         <module name="EqualsHashCode"/>