[DRAFT] feature: recenter line if jump target point is not inside window. (vi-mode)

[sakurawald]

In vim, the jump-back and jump-next will recenter jump target line if the line is not inside the window before jump.

[sakurawald]

The code is formatted by the default formatter provided by lem.
I didn't know why the identation is different from the original file. It's annoy, each time i have to reset the identation differs.

[sakurawald]

Sorry, i didn't notice that 1 line code is deleted accidently. Now the CI tests will pass.

[sakurawald]

I remove the target-point binding in let form, and document the return value of (jump-back) and (jump-next).
It looks clearer.

[sakurawald]

I make this pr a draft, and considering make it a feature in lem.

A new line positioning strategy to re-position where the line should the cursor in after jumping the point. Or to say, a function line-view-position-function to be called after we move-point to a new point.

The strategy can be: none, recenter-current-line-if-new-point-is-not-inside-original-window-view, scroll-line-to-top-of-window, scroll-line-to-bottom-of-window.

We can introduce a new special variable named line-positioning-strategy and making it integrate with the move-point function.