"a" in normal mode types "a" instead of back to insert mode

[Kejun (Albert) Ying]

Hi, thank you for this awesome work! It is a bit unnatural for me that "a" in normal mode types literal "a" instead of back to insert mode. I'm wondering is it a bug or an unimplemented feature? If it is the latter, it shouldn't be hard as it is just equivalent to right arrow + i or l + i

[David Balatero]

Added it!