Correct sanity check for a truncated Kanji character at the end of the changed sequen...

Correct sanity check for a truncated Kanji character at the end of the changed sequence passed to Term_text_cocoa().  Resolves the report of uncleared character in the Japanese version when changing between pages in teh character description (No3.png in https://osdn.net/projects/hengbandforosx/ticket/41228 ).  Also fixes at least some of the cases where the Japanese version garbles item names displayed in the shops (No4.png in ticket 41228).