[refactor] Address review feedback from @reinhapa

Convert version if-else chain in XQueryTree.g to switch-as-expression.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: joewiz

exist-core/src/main/antlr/org/exist/xquery/parser/XQueryTree.g

@@ -267,17 +267,13 @@ throws PermissionDeniedException, EXistException, XPathException
             v:VERSION_DECL
             {
                 final String version = v.getText();
-                if (version.equals("4.0")) {
-                    context.setXQueryVersion(40);
-                } else if (version.equals("3.1")) {
-                    context.setXQueryVersion(31);
-                } else if (version.equals("3.0")) {
-                    context.setXQueryVersion(30);
-                } else if (version.equals("1.0")) {
-                    context.setXQueryVersion(10);
-                } else {
-                    throw new XPathException(v, ErrorCodes.XQST0031, "Wrong XQuery version: require 1.0, 3.0, 3.1, or 4.0");
-                }
+                context.setXQueryVersion(switch (version) {
+                    case "4.0" -> 40;
+                    case "3.1" -> 31;
+                    case "3.0" -> 30;
+                    case "1.0" -> 10;
+                    default -> throw new XPathException(v, ErrorCodes.XQST0031, "Wrong XQuery version: require 1.0, 3.0, 3.1, or 4.0");
+                });
             }
             ( enc:STRING_LITERAL )?
             {