Merge some string literals

Author: garydgregory

src/main/java/org/apache/commons/cli/OptionValidator.java

@@ -129,7 +129,7 @@ static String validate(final String option) throws IllegalArgumentException {
             for (int i = 1; i < chars.length; i++) {
                 final char ch = chars[i];
                 if (!isValidChar(ch)) {
-                    throw new IllegalArgumentException(String.format("The option '%s' contains an illegal " + "character : '%s'.", option, ch));
+                    throw new IllegalArgumentException(String.format("The option '%s' contains an illegal character : '%s'.", option, ch));
                 }
             }
         }

src/test/java/org/apache/commons/cli/help/HelpFormatterTest.java

@@ -354,7 +354,7 @@ void testToSyntaxOptionIterableTest() {
     void testToSyntaxOptionOptionsTest() {
         final HelpFormatter underTest = HelpFormatter.builder().get();
         Options options = getTestGroups();
-        assertEquals("[-1 <arg> | --aon <arg> | --uno <arg>] [--dos <arg> | --dó <arg> | --two <arg>] " + "[--three <arg> | --tres <arg> | --trí <arg>]",
+        assertEquals("[-1 <arg> | --aon <arg> | --uno <arg>] [--dos <arg> | --dó <arg> | --two <arg>] [--three <arg> | --tres <arg> | --trí <arg>]",
                 underTest.toSyntaxOptions(options), "getTestGroup options failed");
 
         // @formatter:off