Wrong CP857 conversion table entry for letter ğ

https://gitlab.com/FreeDOS/base/htmlhelp/-/blob/master/SOURCE/HTMLHELP/CP/CP857.H#L43 contains:

CP_ENTRY (0xA7, 267)

should be, according to https://de.wikipedia.org/wiki/Codepage_857:

CP_ENTRY (0xA7, 287)