fix: remove BOM characters

Author: joewiz

resources/boilerplate/frus-about.xml

@@ -1,4 +1,5 @@
-<div xmlns="http://www.w3.org/1999/xhtml" id="about">
+<?xml version="1.0" encoding="UTF-8"?>
+<div xmlns="http://www.w3.org/1999/xhtml" id="about">
     <h1>About the Electronic Edition</h1>
     <p>The Office of the Historian at the U.S. Department of State has embarked on a program to
         release an ebook edition of the <em>Foreign Relations of the United States</em>