Wrap &lt and &gt symbols in code blocks (#4299)

Author: daymxn

firebase-database/src/main/java/com/google/firebase/database/DataSnapshot.java

@@ -105,12 +105,12 @@ public boolean exists() {
    * returned are:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>String
-   *   <li>Long
-   *   <li>Double
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>String</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * This list is recursive; the possible types for {@link java.lang.Object} in the above list is
@@ -129,12 +129,12 @@ public Object getValue() {
    * returned are:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>String
-   *   <li>Long
-   *   <li>Double
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>String</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * This list is recursive; the possible types for {@link java.lang.Object} in the above list is
@@ -300,8 +300,8 @@ public void remove() {
    * types:
    *
    * <ul>
-   *   <li>Double
-   *   <li>String
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
    * </ul>
    *
    * Note that null is also allowed

firebase-database/src/main/java/com/google/firebase/database/DatabaseReference.java

@@ -126,12 +126,12 @@ public DatabaseReference push() {
    * correspond to the JSON types:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>Long
-   *   <li>Double
-   *   <li>String
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * <br>
@@ -165,12 +165,12 @@ public Task<Void> setValue(@Nullable Object value) {
    * the JSON types:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>Long
-   *   <li>Double
-   *   <li>String
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * <br>
@@ -205,12 +205,12 @@ public Task<Void> setValue(@Nullable Object value, @Nullable Object priority) {
    * correspond to the JSON types:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>Long
-   *   <li>Double
-   *   <li>String
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * <br>
@@ -242,12 +242,12 @@ public void setValue(@Nullable Object value, @Nullable CompletionListener listen
    * value correspond to the JSON types:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>Long
-   *   <li>Double
-   *   <li>String
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * <br>

firebase-database/src/main/java/com/google/firebase/database/MutableData.java

@@ -166,12 +166,12 @@ public String getKey() {
    * returned are:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>String
-   *   <li>Long
-   *   <li>Double
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * This list is recursive; the possible types for {@link java.lang.Object} in the above list is
@@ -267,11 +267,11 @@ public <T> T getValue(@NonNull GenericTypeIndicator<T> t) {
    * the value correspond to the JSON types:
    *
    * <ul>
-   *   <li>Boolean
-   *   <li>Long
-   *   <li>Double
-   *   <li>Map&lt;String, Object&gt;
-   *   <li>List&lt;Object&gt;
+   *   <li><code>Boolean</code>
+   *   <li><code>Long</code>
+   *   <li><code>Double</code>
+   *   <li><code>Map&lt;String, Object&gt;</code>
+   *   <li><code>List&lt;Object&gt;</code>
    * </ul>
    *
    * <br>
@@ -317,8 +317,8 @@ public void setPriority(@Nullable Object priority) {
    * Gets the current priority at this location. The possible return types are:
    *
    * <ul>
-   *   <li>Double
-   *   <li>String
+   *   <li><code>Double</code>
+   *   <li><code>String</code>
    * </ul>
    *
    * Note that null is allowed