Need to compensate for lack of fringes when using TTY

## Overview

I'm dealing with incorrectly displayed timestamps. Imagine a frame split vertically into two windows, with the same chatroom buffer displayed in them. Timestamps in the left one are missing the last char:

```
┌────────┬─────────┐
│a: hey │a: hey │
│ 12:34:5│ 12:34:56│
│ │ │
│ │ │
│ │ │
│ │ │
│ │ │
│ │ │
└────────┴─────────┘
```

Whenever the frame is split vertically into several windows, timestamps are only displayed correctly in the rightmost one.

## Reproducing

0. I ran this in tty, with dimensions 160x57. This may or may not be relevant.

1. Run
```sh
emacs -Q \
-L /usr/share/emacs/site-lisp/dash \
-L /usr/share/emacs/site-lisp/ement \
-L /usr/share/emacs/site-lisp/plz \
-L /usr/share/emacs/site-lisp/s \
-L /usr/share/emacs/site-lisp/ts \
--eval "(require 'ement)" \
--eval "(require 'ement-room-list)"
```
(modulo path to libraries)

2. Eval `(ement-connect "@user:matrix.org" "***")`.

3. Visit a chatroom buffer.

4. Ensure the frame is split vertically into two windows with the same chatroom buffer dispalyed in both of them.

5. Observe incorrectly displayed timestamps in the left window.