chore: checkpoint before Python removal

vendor/clap/examples/demo.md

@@ -0,0 +1,17 @@
+```console
+$ demo --help
+A simple to use, efficient, and full-featured Command Line Argument Parser
+
+Usage: demo[EXE] [OPTIONS] --name <NAME>
+
+Options:
+  -n, --name <NAME>    Name of the person to greet
+  -c, --count <COUNT>  Number of times to greet [default: 1]
+  -h, --help           Print help
+  -V, --version        Print version
+
+$ demo --name Me
+Hello Me!
+
+```
+*(version number and `.exe` extension on windows replaced by placeholders)*