Create a Transient menu to adapt on the fly the width of my buffers
when using writeroom-mode. This commit also adds two other functions:
- `my/writeroom-reset` which resets the width of the buffer to its
default state
- `my/writeroom-fit-buffer` which sets the width of the buffer to be
exactly what is needed to fit the longest line of the buffer
This commit enables eat-mode in Eshell, allowing the use of tools that
normally would not work in Eshell.
It also automatically closes the eat buffer when exiting the shell
instead of keeping it open.
