[SCIM] Japanese translation almost finished

[Yukiko Bando]

Hi!

James Su wrote:
> The Forward key is used to send the original key sequence to client
> app, do not perform any conversion.
> The commit key is used to send the converted string to client app.
> In forward mode, any key sequence will be sent to client directly.
> In input mode, the key sequence will be converted into language
> string, then the result string will be sent to client.

I added the following translations to ja.po and sent it to James.

Please correct them if not appropriate.

Commit Key: 変換確定キー
Forward Key: 直接入力キー

Forward Mode: 直接入力モード
Input Mode: 変換入力モード

Thank you.

Yukiko