This allows an escape code to invoke user-defined extensions found in
/home/rahm/.local/bin/alacritty-ext.sh. The terminal passes to this
script the escape-code arguments.

This allows things like opening links in the browser even through an ssh
connection.

This was not a _real_ violation and was _expected_, though for rust
to not complain clone FD properly...

This patch fixes an issue with signal handling where Alacritty would
permanently create one signal handling FD for each alacritty window
created by an instance. This FD was never released, causing a leak of
the FD.

Closes #7983.

Closes #7886.

This is only an update to the development version and does not represent
a stable release.

Winit explicitly states that the window is not focused by default and
the `Focused` event will deliver the state later on.

Also start adding notable changes to alacritty_terminal in its own
CHANGELOG.

Closes #7866.