Filenames in Identification in USFM Documentation.

[DavidHaslam]

USFM filenames in Windows really do need the underscore after the first two digits!

There's a very annoying problem with Windows Explorer when files are sorted in the order of filenames.

Without the underscore to separate the two digit file number from the three character book abbreviation, all the books whose abbreviation begins with a numeral end up after 67REV*.usfm

This is important for software utilities which process the files in filename order.

[DavidHaslam]

Relates to this page in the documentation:

https://ubsicap.github.io/usfm/identification/books.html

This table lists all the standard 3-character book identifiers that can be entered after the \id marker at the top of each USFM file. Some scripture editors like ParaTExt may also include the number shown for each book in the filename for that book.

It would be useful to add my observation as a footnote to the word filename.