Use Java modern features/APIs (#357)

* refactor: Run openrewrite to use Java 17 features

This mainly uses:

- Text blocks: https://openjdk.org/jeps/378
- Pattern matching: https://openjdk.org/jeps/394

* refactor: a few usages of newer Collections APIs

jte-jsp-converter/src/main/java/example/JteContext.java

@@ -17,14 +17,14 @@ public class JteContext {
     public static boolean isEmpty(Object obj) {
         if (obj == null) {
             return true;
-        } else if (obj instanceof String) {
-            return ((String) obj).length() == 0;
-        } else if (obj instanceof Object[]) {
-            return ((Object[]) obj).length == 0;
-        } else if (obj instanceof Collection) {
-            return ((Collection<?>) obj).isEmpty();
+        } else if (obj instanceof String string) {
+            return string.isEmpty();
+        } else if (obj instanceof Object[] objects) {
+            return objects.length == 0;
+        } else if (obj instanceof Collection<?> collection) {
+            return collection.isEmpty();
         } else {
-            return obj instanceof Map && ((Map<?, ?>) obj).isEmpty();
+            return obj instanceof Map<?, ?> m && m.isEmpty();
         }
     }
 

jte-jsp-converter/src/test/java/gg/jte/convert/jsp/JspToJteConverterTest.java

@@ -155,8 +155,10 @@ void simpleTagWithNotYetConvertedTags() {
         givenUsecase("simpleTagWithNotYetConvertedTags");
         Throwable throwable = catchThrowable(() -> whenJspTagIsConverted("my/simple.tag", "tag/my/simple.jte"));
         assertThat(throwable).isInstanceOf(UnsupportedOperationException.class).hasMessage(
-              "The tag <my:simple-dependency1/> is used by this tag and not converted to jte yet. You should convert <my:simple-dependency1/> first. If this is a tag that should be always converted by hand, implement getNotConvertedTags() and add it there.\n" +
-              "The tag <my:simple-dependency2/> is used by this tag and not converted to jte yet. You should convert <my:simple-dependency2/> first. If this is a tag that should be always converted by hand, implement getNotConvertedTags() and add it there."
+              """
+              The tag <my:simple-dependency1/> is used by this tag and not converted to jte yet. You should convert <my:simple-dependency1/> first. If this is a tag that should be always converted by hand, implement getNotConvertedTags() and add it there.
+              The tag <my:simple-dependency2/> is used by this tag and not converted to jte yet. You should convert <my:simple-dependency2/> first. If this is a tag that should be always converted by hand, implement getNotConvertedTags() and add it there.\
+              """
         );
     }
 

jte-kotlin/src/main/java/gg/jte/compiler/kotlin/KotlinClassCompiler.java

@@ -91,7 +91,7 @@ public void report(CompilerMessageSeverity severity, @SuppressWarnings("Nullable
                         line = location.getLine();
                     }
 
-                    errors.add(String.format("%s%n%s:%d:%d%nReason: %s", location.getLineContent(), location.getPath(),
+                    errors.add("%s%n%s:%d:%d%nReason: %s".formatted(location.getLineContent(), location.getPath(),
                             location.getLine(),
                             location.getColumn(), s));
                 } else {