Use var in modernCode where type is redundant with RHS

Replace explicit type declarations with var in 5 patterns where
the type is already obvious from the right-hand side (factory methods,
getInstance, class literals), making the modern examples consistent
with the type-inference-with-var pattern.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: brunoborges

content/datetime/hex-format.yaml

@@ -17,7 +17,7 @@ oldCode: |-
   int val = Integer.parseInt(
       "FF", 16);
 modernCode: |-
-  HexFormat hex = HexFormat.of()
+  var hex = HexFormat.of()
       .withUpperCase();
   String s = hex.toHexDigits(
       byteValue);

content/enterprise/jdbc-resultset-vs-jpa-criteria.yaml

@@ -33,10 +33,10 @@ modernCode: |-
 
   public List<User> findActiveAboveAge(
           String status, int minAge) {
-      CriteriaBuilder cb = em.getCriteriaBuilder();
-      CriteriaQuery<User> cq =
+      var cb = em.getCriteriaBuilder();
+      var cq =
           cb.createQuery(User.class);
-      Root<User> root = cq.from(User.class);
+      var root = cq.from(User.class);
       cq.select(root).where(
           cb.equal(root.get("status"), status),
           cb.greaterThan(root.get("age"), minAge));

content/enterprise/manual-transaction-vs-declarative.yaml

@@ -37,8 +37,8 @@ modernCode: |-
       @Transactional
       public void transferFunds(Long from, Long to,
                                 BigDecimal amount) {
-          Account src = em.find(Account.class, from);
-          Account dst = em.find(Account.class, to);
+          var src = em.find(Account.class, from);
+          var dst = em.find(Account.class, to);
           src.debit(amount);
           dst.credit(amount);
       }

content/io/path-of.yaml

@@ -13,7 +13,7 @@ oldCode: |-
   Path path = Paths.get("src", "main",
       "java", "App.java");
 modernCode: |-
-  Path path = Path.of("src", "main",
+  var path = Path.of("src", "main",
       "java", "App.java");
 summary: "Use Path.of() — the modern factory method on the Path interface."
 explanation: "Path.of() is a factory method added directly to the Path interface,\

content/security/key-derivation-functions.yaml

@@ -18,7 +18,7 @@ oldCode: |-
   SecretKey key =
       factory.generateSecret(spec);
 modernCode: |-
-  KDF kdf = KDF.getInstance("HKDF-SHA256");
+  var kdf = KDF.getInstance("HKDF-SHA256");
   SecretKey key = kdf.deriveKey(
       "AES",
       KDF.HKDFParameterSpec