FR: Add TAB for word selection

[stevenlis]

Hi.

In addition to enter and space , could you please consider adding tab as a word selection key as well.

For example, when I write code, I use tab for code completion (a common keyboard setting in code editors such as vscode). When I have to insert a comment or something, I activate hallelujahIM to reply on its word completion, but it doesn't support tab selection.

I found it's very hard to remember the different selection patterns, and adding a toggle for it would be really helpful.

[dongyuwei]

It's doable, but I don't have enough free time to implement/debug it.