Suggest documentation for syntax highlighting issues on Windows

Suggest documentation to preemptively address user issues like #6704

MANUAL.txt

@@ -1,4 +1,5 @@
----
+---byte-or
+
 title: Pandoc User's Guide
 author: John MacFarlane
 date: September 9, 2024
@@ -7262,7 +7263,7 @@ use `--print-highlight-style` to generate a JSON `.theme` file which
 can be modified and used as the argument to `--highlight-style`. To
 get a JSON version of the `pygments` style, for example:
 
-    pandoc --print-highlight-style pygments > my.theme
+    pandoc -o my.theme --print-highlight-style pygments
 
 Then edit `my.theme` and use it like this:
 
@@ -7275,6 +7276,9 @@ file](https://docs.kde.org/stable5/en/kate/katepart/highlight.html).
 Before writing your own, have a look at KDE's [repository of syntax
 definitions](https://github.com/KDE/syntax-highlighting/tree/master/data/syntax).
 
+If you receive an error that pandoc "Could not read highlighting theme",
+check that the JSON file is encoded with UTF-8 and has no Byte-Order Mark (BOM).
+
 To disable highlighting, use the `--no-highlight` option.
 
 [skylighting]: https://github.com/jgm/skylighting