add Excel to the BOM example

Author: osiegmar

docs/src/content/docs/guides/Examples/byte-order-mark.mdx

@@ -13,7 +13,7 @@ that serves as a header to indicate the file's Unicode encoding, such as UTF-8,
 For UTF-16 and UTF-32, the BOM header also indicates the byte order (big-endian or little-endian).
 
 While UTF-8 is the standard encoding for most text files today,
-some applications still use the BOM header to explicitly specify the file's encoding.
+some applications (like Microsoft Excel) still use the BOM header to explicitly specify the file's encoding.
 :::
 
 Enabling automatic BOM header detection can impact performance.
@@ -34,6 +34,8 @@ The following table shows the BOM headers for different Unicode encodings that F
 | UTF-32 (BE) | `00 00 FE FF`    |
 | UTF-32 (LE) | `FF FE 00 00`    |
 
+The UTF-8 BOM header is the most common one that is also used by Microsoft Excel.
+
 ## Example
 
 In the following example, a CSV file with a BOM header is created and read using FastCSV.

example/src/main/java/example/ExampleCsvReaderWithBomHeader.java

@@ -1,6 +1,6 @@
 package example;
 
-import static java.nio.charset.StandardCharsets.UTF_16LE;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -25,17 +25,16 @@ public static void main(final String[] args) throws IOException {
         }
     }
 
-    // Create a file with content encoded in UTF-16 little-endian and
-    // a corresponding BOM header
+    // Create a file with UTF-8 encoding and a corresponding BOM header
     static Path prepareTestFile() throws IOException {
         final Path tmpFile = Files.createTempFile("fastcsv", ".csv");
         tmpFile.toFile().deleteOnExit();
 
         try (var out = Files.newOutputStream(tmpFile);
-             var csv = CsvWriter.builder().build(out, UTF_16LE)) {
+             var csv = CsvWriter.builder().build(out, UTF_8)) {
 
-            // Manually write UTF-16LE BOM header
-            out.write(new byte[]{(byte) 0xff, (byte) 0xfe});
+            // Manually write UTF-8 BOM header
+            out.write(new byte[]{(byte) 0xEF, (byte) 0xBB, (byte) 0xBF});
 
             csv.writeRecord("a", "o", "u");
             csv.writeRecord("ä", "ö", "ü");