PropertyName.java: fix rendering of code sample

Author: dconeybe

firebase-firestore/src/main/java/com/google/firebase/firestore/PropertyName.java

@@ -23,29 +23,25 @@
  * Marks a field to be renamed when serialized.
  *
  * <h3>Kotlin Note</h3>
- * When applying this annotation to a property of a Kotlin class, both the <code>@get</code> and
- * <code>@set</code> use-site targets should be used.
+ * When applying this annotation to a property of a Kotlin class, both the {@code @get} and
+ * {@code @set} use-site targets should be used.
  * <p>
  * Here is an example of a class that can both be written into and read from Firestore whose
- * <code>foo</code> property will be stored into and read from a field named "my_foo" in the
+ * {@code foo} property will be stored into and read from a field named {@code my_foo} in the
  * Firestore document:
  * <pre>
- * data class Pojo(
- *   @get:PropertyName("my_foo")
- *   @set:PropertyName("my_foo")
- *   var foo: String? = null
- * ) {
+ * data class Pojo(@get:PropertyName("my_foo") @set:PropertyName("my_foo") var foo: String? = null) {
  *   constructor() : this(null) // Used by Firestore to create new instances
  * }
  * </pre>
  * <p>
  * If the class only needs to be <em>written</em> into Firestore (and not read from Firestore) then
  * the class can be simplified as follows:
  * <pre>
- * data class Pojo(@get:PropertyName("my_foo") val foo: String? = null)
+ * {@literal data class Pojo(@get:PropertyName("my_foo") val foo: String? = null)}
  * </pre>
- * That is, <code>var</code> can be tightened to <code>val</code>, the secondary no-argument
- * constructor can be omitted, and the <code>@set</code> use-site target can be omitted.
+ * That is, {@code var} can be tightened to {@code val}, the secondary no-argument constructor can
+ * be omitted, and the {@code @set} use-site target can be omitted.
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ElementType.METHOD, ElementType.FIELD})