Add prefix to the block after resolutionStrategy block when non existed (standalone scripts where only dependencies block existed without prefix) (#6784)

Author: Jenson3210

rewrite-gradle/src/main/java/org/openrewrite/gradle/DependencyConstraintToRule.java

@@ -380,7 +380,14 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu
                             .map(J.MethodInvocation.class::cast)
                             .findFirst()
                             .orElseThrow(() -> new IllegalStateException("Unable to create a new configurations.all block"));
-                    return cu.withStatements(ListUtils.insert(cu.getStatements(), m, insertionIndex));
+                    List<Statement> newStatements = ListUtils.insert(cu.getStatements(), m, insertionIndex);
+                    if (insertionIndex == 0) {
+                        newStatements = ListUtils.map(newStatements, (i, stat) ->
+                                i == 1 && stat.getPrefix().getWhitespace().isEmpty()
+                                        ? stat.withPrefix(stat.getPrefix().withWhitespace("\n\n"))
+                                        : stat);
+                    }
+                    return cu.withStatements(newStatements);
                 } else {
                     K.CompilationUnit cu = (K.CompilationUnit) sourceFile;
                     assert cu != null;
@@ -425,7 +432,14 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu
                     final int finalInsertionIndex = insertionIndex;
                     return cu.withStatements(ListUtils.mapFirst(cu.getStatements(), arg -> {
                         if (arg == block) {
-                            return block.withStatements(ListUtils.insert(block.getStatements(), m, finalInsertionIndex));
+                            List<Statement> newStatements = ListUtils.insert(block.getStatements(), m, finalInsertionIndex);
+                            if (finalInsertionIndex == 0) {
+                                newStatements = ListUtils.map(newStatements, (i, stat) ->
+                                        i == 1 && stat.getPrefix().getWhitespace().isEmpty()
+                                                ? stat.withPrefix(stat.getPrefix().withWhitespace("\n\n"))
+                                                : stat);
+                            }
+                            return block.withStatements(newStatements);
                         }
                         return arg;
                     }));