[Feature Request] Allow sending Shift+Enter to applications

[SlugFiller]

Currently, both \n and \r are interpreted as just Enter, and there doesn't seem to be a way to add modifiers to keys sent.

Many chat applications interpret Enter as "send", and Shift+Enter as newline, for multi-line messages. Currently, WinCompose doesn't allow creating multi-line messages, other than creating them line by line, and pressing Shift+Enter manually.

So, it would be nice if it was possible to add modifier keys to the sent string, or at least have some symbol for Shift+Enter, e.g. \r