checkstyle.xml: add 3 modules

Author: stephengold

config/checkstyle/checkstyle.xml

@@ -106,6 +106,7 @@
         <!-- See https://checkstyle.org/checks/coding -->
         <module name="AvoidDoubleBraceInitialization"/>
         <module name="AvoidNoArgumentSuperConstructorCall"/>
+        <module name="ConstructorsDeclarationGrouping"/>
         <module name="CovariantEquals"/>
         <module name="DefaultComesLast"/>
         <module name="EmptyStatement"/>
@@ -197,6 +198,7 @@
         <module name="CommentsIndentation">
             <property name="tokens" value="SINGLE_LINE_COMMENT, BLOCK_COMMENT_BEGIN"/>
         </module>
+        <module name="NoCodeInFile"/>
         <module name="OuterTypeFilename"/>
         <module name="UpperEll"/>
 
@@ -272,6 +274,10 @@
 
         <!-- Regexp checks:                           -->
         <!-- See https://checkstyle.org/checks/regexp -->
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="static (abstract|final|native|package|private|protected)|(native|package|private|protected) (abstract|final)"/>
+            <property name="message" value="Modifiers must appear in alphabetical order."/>
+        </module>
         <module name="RegexpSinglelineJava">
             <property name="format" value="\{[ ]+\}"/>
             <property name="message" value="Empty blocks must not contain spaces."/>