Function: japanese-zenkaku-region

Convert hankaku' chars in the region to Japanese `zenkaku' chars.
`Zenkaku' chars belong to `japanese-jisx0208'
`Hankaku' chars belong to `ascii' or `japanese-jisx0201-kana'.
Optional argument KATAKANA-ONLY non-nil means to convert only KATAKANA char.

(fn FROM TO &optional KATAKANA-ONLY)