Get garbled in non-UTF8 file

[KSR-Yasuda]

It gets garbled on non-UTF8 files.

For example, the document below is written in charset EUC-JP.

• https://i-red.info/docs/jfp/usbmon.txt

Without MarkdownPreviewPlus, it is displayed in EUC-JP correctly.

With MarkdownPreviewPlus enabled, it styles the document in the file encode EUC-JP at first.

However, after a while, it wrongly changes charset to UTF-8.

Environment

• Markdown Preview Plus v0.7.24
• Chrome 111.0.5563.65 (Official Build) （64 bits） (cohort: 111_Win_64_Ramup)
• Windows 10 Pro 22H2 (Version 10.0.19045.2604)

[volca]

The page doesn't send encoding in the response header. the header is

content-type: text/plain

e.g. it should contains the charset part

Content-Type: text/html; charset=utf-8