Allow shift+enter to insert new line in commit message

[andresovela]

Is your feature request related to a problem? Please describe.
It should be possible to create a multi-line commit message.

Describe the solution you'd like
Press shift+enter to enter a new line.

Describe alternatives you've considered
None.

[extrawurst]

did you know: you can open the external editor for this?

otherwise its probably a dup of #711

[andresovela]

External editor? No, how?

[extrawurst]

external editor support was added in 0.8.0.
see this animation (notice the Open editor command in the action-bar on the bottom):
https://github.com/extrawurst/gitui/blob/master/assets/vi_support.gif

[andresovela]

I see, cool thanks!

[crispinb]

Any chance of reconsidering this? External editor support is a nice additional feature, but seems like an unnecessary additional step for many commit messages of just a few lines. Shift + Enter is so common in this kind of context I tried it a few times before realising it really didn't enter a newline ;)

[extrawurst]

See #1171