RUM-8673 Add docs to deprecated API

Author: maciejburda

dd-sdk-android-core/src/main/kotlin/com/datadog/android/Datadog.kt

@@ -259,6 +259,17 @@ object Datadog {
         sdkCore.setUserInfo(id, name, email, extraInfo)
     }
 
+    /**
+     * Sets the user information.
+     *
+     * @param id (nullable) a unique user identifier (relevant to your business domain)
+     * @param name (nullable) the user name or alias
+     * @param email (nullable) the user email
+     * @param extraInfo additional information. An extra information can be
+     * nested up to 8 levels deep. Keys using more than 8 levels will be sanitized by SDK.
+     * @param sdkCore SDK instance to set user info in. If not provided, default SDK instance
+     * will be used.
+     */
     @JvmStatic
     @JvmOverloads
     @Deprecated(