API Request: Getting the correct indentation level of a line

[Chillee]

For VSCodeVim/Vim#1017, we need to be able to move the cursor to the correct indentation level.

We can't just insert a tab, because when the cursor is at the beginning of the line, there's no way to know whether we should insert a tab or not.

Alternatively, an API call that indents the current line to the correct level would also be suitable for our purposes.

[Chillee]

For our purposes, this issue being implemented also fixes this issue:

#19847 (comment)

[Chillee]

I think this is not as necessary with the other issue linked, so I'm going to close this issue for now. In addition, neovim integration also solves this issue for us.