Document Python 3.13 on Debian 12: the apt python3 is 3.11

No issue closed: documentation fix found while verifying the Debian commands.

wiki/Install.da.md

@@ -15,6 +15,8 @@ python -m pip install -e ".[dev]"
 
 ## Linux Debian
 
+På Debian 13 (trixie) eller nyere er `python3` 3.13:
+
 ```bash
 sudo apt install python3 python3-venv
 python3 -m venv .venv
@@ -23,6 +25,19 @@ python -m pip install --upgrade pip
 python -m pip install -e ".[dev]"
 ```
 
+På Debian 12 (bookworm) er `python3` 3.11, og `pip` nægter at installere projektet (`requires a different Python`). Hent Python 3.13 med [uv](https://docs.astral.sh/uv/) og brug den til `.venv`:
+
+```bash
+sudo apt install python3 python3-venv
+python3 -m venv .uvenv
+.uvenv/bin/python -m pip install uv
+.uvenv/bin/uv python install 3.13
+.uvenv/bin/uv venv --seed --python 3.13 .venv
+source .venv/bin/activate
+python -m pip install --upgrade pip
+python -m pip install -e ".[dev]"
+```
+
 ## macOS
 
 ```bash