Fix javadoc character escaping

Author: scordio

src/main/java/org/assertj/core/api/AbstractFileAssert.java

@@ -1017,7 +1017,7 @@ public SELF isEmpty() {
   }
 
   /**
-   * Verify that the actual {@code File} is not empty (i.e. the file size > 0).
+   * Verify that the actual {@code File} is not empty (i.e. the file size > 0).
    * <p>
    * Example:
    * <pre><code class='java'> File file = File.createTempFile(&quot;tmp&quot;, &quot;txt&quot;);