shell: add support for vim/hybrid styles in term/ansi-term buffers.

[ellakk]

I was trying out the vim editing style today and noticed that the cursor is stuck in normal/visual mode in term buffers, you can't move around and you cant edit/copy anything. This solves it.
This commit also ensured the cursor goes to the prompt if the cursor enters insert/hybrid mode from a different line than the prompt line.
Fixes: #10779.

[giuscri]

Inside a project, a shell is no longer spawned with SPC '. Instead, current window is split and the same buffer is shown twice.

This is what's printed in *Messages*:

term-char-mode: Wrong type argument: processp, nil
Error in post-command-hook (evil-mode-check-buffers): (wrong-type-argument processp nil)

[ellakk]

Well that sucks, I'm gonna have a look at it when i get home or tomorrow. Did this happen with the same setup you posted in #10956. I've been using it on emacs 26.1 and seems to work just fine but ill investigate.

[OkIdeal0]

I had the same issue as @giuscri. The problem seems to be that (term-char-mode) is called before the process is properly set up. Changing term-enable-char-mode-maby-goto-prompt to

(defun spacemacs//term-enable-char-mode-maby-goto-prompt ()
     (when (eq major-mode 'term-mode)
       (when (get-buffer-process (current-buffer))
         (term-char-mode)
         (if (not (eq (line-number-at-pos (point))
                      (line-number-at-pos (marker-position (term-process-mark)))))
             (goto-char (term-process-mark))))))

works for me. This is the approach taken by evil-collections.

[ellakk]

Thanks @OkIdeal0, updated pr.

[giuscri]

It seems to work.

Yet, when I copy from a buffer using y and I use paste to a terminal using p the following happens

Basically pasting deletes the start of the line when in Normal mode. It reappears when you're back into Insert mode.

[brandonwillard]

Why not use term-goto-process-mark-maybe?