checkstyle.xml: refactor 5 regexps

Author: stephengold

config/checkstyle/checkstyle.xml

@@ -28,7 +28,7 @@
     <!-- Regexp checks:                           -->
     <!-- See https://checkstyle.org/checks/regexp -->
     <module name="RegexpSingleline">
-        <property name="format" value="\s+$"/>
+        <property name="format" value="\s$"/>
         <property name="message" value="Line has trailing whitespace."/>
     </module>
 
@@ -177,7 +177,7 @@
         <module name="RequireEmptyLineBeforeBlockTagGroup"/>
         <module name="SingleLineJavadoc"/>
         <module name="SummaryJavadoc">
-            <property name="forbiddenSummaryFragments" value="^@return the *|^This method returns |^A [{]@code [a-zA-Z0-9]+[}]( is a )"/>
+            <property name="forbiddenSummaryFragments" value="^@return the *|^This method returns |^A [{]@code [0-9A-Za-z]+[}]( is a )"/>
             <property name="period" value=""/>
         </module>
 
@@ -221,16 +221,16 @@
             <message key="name.invalidPattern" value="Interface type name ''{0}'' must match pattern ''{1}''."/>
         </module>
         <module name="LambdaParameterName">
-            <property name="format" value="^[a-z][a-zA-Z]{0,13}$"/>
+            <property name="format" value="^[a-z][A-Za-z]{0,13}$"/>
             <message key="name.invalidPattern" value="Lambda parameter name ''{0}'' must match pattern ''{1}''."/>
         </module>
         <module name="LocalFinalVariableName"/>
         <module name="LocalVariableName">
-            <property name="format" value="^[a-z][a-zA-Z0-9]{0,19}$"/>
+            <property name="format" value="^[a-z][0-9A-Za-z]{0,19}$"/>
             <message key="name.invalidPattern" value="Local variable name ''{0}'' must match pattern ''{1}''."/>
         </module>
         <module name="MemberName">
-            <property name="format" value="^[a-z][a-zA-Z0-9]{0,19}$"/>
+            <property name="format" value="^[a-z][0-9A-Za-z]{0,19}$"/>
             <message key="name.invalidPattern" value="Member name ''{0}'' must match pattern ''{1}''."/>
         </module>
         <module name="MethodName">