Description of the Issue

NFO Files are incorrectly recognized with encoding OEM-US.

Steps to Reproduce the Issue

1. Create in notepad some text file with nfo extension.
2. Open this file in Notepad++.
3. You will see OEM-US encoding in the bottom information line.
4. If you change the extension to the txt, the encoding will be correctly recognized.

Expected Behavior

Notepad++ should detect encoding.

Actual Behavior

Notepad++ detects always at nfo files OEM-US encoding.

Debug Information

Notepad++ v7.9.1 (64-bit)
Build time : Nov 2 2020 - 01:07:46
Path : C:\Program Files\Notepad++\notepad++.exe
Admin mode : ON
Local Conf mode : OFF
OS Name : Windows 10 Enterprise 2016 LTSB (64-bit)
OS Version : 1607
OS Build : 14393.4046
Current ANSI codepage : 1250
Plugins : mimeTools.dll NppConverter.dll NppExport.dll