flake/dev: use nix-shell shebangs for scripts

Allow running the scripts directly without entering the devshell.

flake/dev/diff-plugins.py

@@ -1,4 +1,5 @@
-#!/usr/bin/env python3
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3
 
 import json
 import re

flake/dev/list-plugins/default.nix

@@ -10,6 +10,8 @@
       package = pkgs.writers.writePython3Bin "list-plugins" {
         # Disable flake8 checks that are incompatible with the ruff ones
         flakeIgnore = [
+          # Thinks shebang is a block comment
+          "E265"
           # line too long
           "E501"
           # line break before binary operator

flake/dev/list-plugins/list-plugins.py

@@ -1,3 +1,6 @@
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3
+
 import glob
 import os
 import re

flake/dev/locate-lsp-packages.py

@@ -1,5 +1,5 @@
-#!/usr/bin/env python3
-# This script requires nix-locate
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3 nix-index
 
 import json
 import os

flake/dev/new-plugin.py

@@ -1,4 +1,5 @@
-#!/usr/bin/env python3
+#!/usr/bin/env nix-shell
+#!nix-shell -i python3 -p python3
 
 import os
 import re