INSTALL: Update Debian package status

Also, make the note generic, to omit the need to update it "constantly".

Closes #76

INSTALL.md

@@ -23,32 +23,8 @@ Thanks to [Francois_B](https://www.sciunto.org/), there is an package available
 
 ## Debian
 
-There a package available in Debian *buster/sid*. The package [doesn't include
-the Nautilus extension yet](https://bugs.debian.org/910491).
-
-For Debian 9 *stretch*, there is a way to install it *manually*:
-
-```
-# apt install python3-mutagen python3-gi-cairo gir1.2-gdkpixbuf-2.0 libimage-exiftool-perl gir1.2-glib-2.0 gir1.2-poppler-0.18 ffmpeg
-# apt install bubblewrap  # if you want sandboxing
-$ git clone https://0xacab.org/jvoisin/mat2.git
-$ cd mat2
-$ ./mat2
-```
-
-and if you want to install the über-fancy Nautilus extension:
-
-```
-# apt install gnome-common gtk-doc-tools libnautilus-extension-dev python-gi-dev python3-dev build-essential
-$ git clone https://github.com/GNOME/nautilus-python
-$ cd nautilus-python
-$ PYTHON=/usr/bin/python3 ./autogen.sh
-$ make
-# make install
-$ mkdir -p ~/.local/share/nautilus-python/extensions/
-$ cp ../nautilus/mat2.py ~/.local/share/nautilus-python/extensions/
-$ PYTHONPATH=/home/$USER/mat2 PYTHON=/usr/bin/python3 nautilus
-```
+There is a package available in [Debian
+stable](https://packages.debian.org/search?keywords=mat2&searchon=names&suite=stable&section=all).
 
 ## Fedora